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MODERN 

STEAM ENGINEERING 

' By GARDNER D. HISCOX, M.E. 

INCLUDING AN ELECTRICAL SECTION 

By NEWTON HARRISON, E.E. 



















Duplex Tandem Compound Corliss Condensing-Engine 





































































































































































































MODERN 

STEAM ENGINEERING 

IN THEORY AND PRACTICE 


A NEW, COMPLETE, AND PRACTICAL WORK FOR 

Steam-Users, Electricians, Firemen, and Engineers 

CONTAINING LATEST PRACTICAL INFORMATION ON 

BOILERS AND THEIR ADJUNCTS; ECONOMY OF STEAM-MAKING AND 
ITS USE FROM THE FUEL TO THE CONDENSER, WITH ILLUSTRATED 
DETAILS OF STEAM-ENGINE PARTS; SUPERHEATED STEAM, ITS 
USE AND ECONOMY; DETAILS OF SLIDE-VALVE AND HIGH-SPEED 
ENGINES; CORLISS, COMPOUND, AND TRIPLE-EFFECT ENGINES; THE 
STEAM-TURBINE AND ITS WORK; THE COST OF STEAM POWER, 
ITS APPLICATION AND OPERATION IN POWER PLANTS FOR ELEC¬ 
TRIC GENERATION, PUMPING, REFRIGERATION, AND ELEVATORS 

OVER TWO HUNDRED QUESTIONS, WITH THEIR ANSWERS, LIKELY TO 
BE ASKED BY THE EXAMINING BOARDS, ARE GIVEN, AS 
WELL AS FORTY TABLES OF THE PROPERTIES OF 
STEAM FOR POWER AND OTHER USES 

By GARDNER D. HISCOX, M.E. 

P ... . 

CONTAINING CHAPTERS ON ELECTRICAL ENGINEERING BY 

NEWTON HARRISON, E.E. 


) > 
> > > 


ILLUSTRATED BY OVER 400 SPECIALLY MADE ENGRAVINGS 

THIRD EDITION 
























/ 

6 







Copyrighted, 1913 and 1906, by 

THE NORMAN W. HENLEY PUBLISHING COMPANY 


__ _ - 


Note.—E ach and every illustration in this book was 
specially made for it, and is fully covered by copyright. 


< 4 

r f « 



COMPOSITION, PRINTING, AND ELECTROTYPING 
BY THE TROW PRESS, NEW YORK, U. S. A. 



©CI.A332688 









PREFACE 


It has been the aim of the author in the production of this work 
to fully meet the wants of the student and engineer in all the prac¬ 
tical requirements for obtaining a mastery in the application and use 
of steam for power and other purposes in the full range of its use¬ 
fulness. 

A further object has been to bring the mathematical side of 
Steam-Engineering into such practical conditions that the engineer 
or student may be able to grasp the whole subject with only ordinary 
arithmetical acquirements by means of the figured repetition of the 
formulas. 

In the forty-two tables included will be found a ready reference, 
covering all conditions of the properties of steam and its application 
for the production of power, ratios, engine parts and proportions, 
most useful in the service now devolved upon the duties of a suc¬ 
cessful engineer. 

Owing to the wide experience of the author, who well knows the 
points a book like this must cover to be of greatest service to the 
men for whom it is written, he has treated at length the subject of 
Superheated Steam and the practical operation of the Plain Slide- 
and Piston-Valves and their gear, the Corliss Valves and valve-gear, 
also the Triple- and Quadruple-Expansion Engine and the work of 
the Indicator, as well as the Steam-Turbine, which is now coming to 
the front as a power-producer. 

The duties of an Engineer, who is entrusted with the management 
and use of Steam in a private or public capacity, are given, as well as 
chapters on Pefrigeration-Plants, Elevators, and Electric-Light Plants. 

Questions as asked by the Examining Board are included, as well 
as their answers, which will prove of greatest help to those prepar¬ 
ing for and desiring to procure a License as a Steam-Engineer. 

Much time has been spent and great care taken in the prepara¬ 
tion of this work, and the author trusts that it will many times over 
compensate the reader for its perusal. 


Gardner D. Hiscox. 



CONTENTS 


CHAPTER I 

PAGE 

Historical, early progress of the steam-engine.15-23 

CHAPTER II 

Steam and its properties, below atmospheric pressure; boiling temperatures, 
elastic force of vapor; heat of evaporation and quantity evaporated 
62° to 212°; boiling fluids above 212°; boiling in vacuo; salt-pan; 
sugar-pan—four tables.24-30 

CHAPTER III 

Generation of steam; furnaces and their adjuncts; fuels; wood, coal, lignite, 
turf, coke, sawdust, bagasse, straw, petroleum, gas; efficiency and 
economy of fuels; boiler-furnaces, grate-bars, stokers, link-grates; 
liquid fuel trials; efficiency; oil-burners of various types, one table 31-48 

CHAPTER IV 

Types of boilers; Stevens, cylinder, flue, tubular, Galloway, boiler-settings; 
internal-fired, marine, down-draught, Herreshoff, Thornycroft, Wood, 

Du Temple, Cahall, duplex, Sterling, Babcock & Wilcox, and vertical 
boilers; horse-power rating of boilers; heating and grate-surface; table; 
indicators of boiler-control, safety-valve areas and computation; lever 
safety-valve, differential, pop; quick-opening water-gauge; recording- 
gauge; fusible plugs; strength of boilers; shell, lap-joints, proportions 
for joints, table; hydraulic test, working pressures, stays, braces, 
five tables..49-73 


CHAPTER V 

Boiler-chimney and its work; draught formulas, diagram, draught-pressures, 
table; draught-gauge, size and height of chimneys, table, steel and brick 
chimneys; firing and chimney-draught; forced-draught steam-blowers, 
Korting and fan-blowers; two tables.74-83 

CHAPTER VI 

Heat-economy of the feed-water; saving of fuel, table; tube-surface of heat¬ 
ers, table; formulas, multicoil heater, open heater, Berryman, Wain- 
wright, Cookson, filter, and Hoppes heater; Green economizer, two 
tables.84-93 


9 



10 


CONTENTS 


CHAPTER VII 

PAGE 

Injector and steam-pump; velocity of steam and water, table, formulas; 
Penberthy, Little Giant, Lunkenheimer, Metropolitan, Korting, and 
exhaust-injector, efficiency; steam-pump and its work; pump-lift heads, 
table; cylinder-proportions, formula for friction-head; Knowles, Worth¬ 
ington, Deane, Cameron, McGowan, Guild & Garrison, and Blake pumps; 
pump-valves; strainers and air-chambers, two tables . . . 94-110 

CHAPTER VIII 

Incrustation in boilers and its remedy; boiler compounds, purification of 
feed-water; table, purifying apparatus; standard chemicals, settling- 
tanks; factor of evaporation, table, formulas; the jet-condenser, siphon- 
condenser, ejector-condenser, water required for condensing, table, 
formula, surface and combination condensers; concentric tube and 
spray-condensers; exhaust-separators; air- and circulating-pump, 
Edwards air-pump; water-cooling towers, high-vacuum installation with - 
cooling-tower, three tables.111-129, 


CHAPTER IX 

Steam above atmospheric pressure, diagram of steam-generation, qualities 
of steam, specific heat, latent heat; formulas and examples, critical 
temperature, formulas for pressure, temperature and volume of steam; 
examples, ratios, total heat-units; tables of the properties of saturated 
steam, one table.130-139 

CHAPTER X 

Flow of steam through orifices, nozles, and pipes; formulas and examples, 
straight nozle, expanding-nozle, diverging and nozle of best form; 
formulas and examples for velocity and dryness of steam; table of 
pressures, velocities and dryness by expansion, value of x, diagram of 
theoretical expansion-curves; energy of steam; flow of steam through 
long pipes; formulas and table; friction and loss of head, two tables 140-146 

CHAPTER XI 

Superheated steam and its work; generation, economy, expansion, increased 
volume; superheater, cost, action in cylinders, in turbines, efficiency, 
specific volume, table, formula and example, consumption by super¬ 
heat for power, table; tests marine and locomotive, tests in Europe; 
rescue of heat from the chimney; waste of heat in steam-making, 
specific-heat formulas and examples; table of total heat; superheaters 
and their construction; Buckley and Metesser superheaters; rear cham¬ 
ber, locomotive and separate chamber superheaters; Schwoerer and 
Foster types; Babcock & Wilcox and Schmidt system; management, 
factor of safety, requirement and economy of superheaters; the measure¬ 
ment of steam, sale of steam, three tables.147-170 



CONTENTS 


11 


CHAPTER XII 

PAGE 

Adiabatic expansion of steam; ratio formulas, exponents, specific heat at 
constant pressure, constant volume; dryness, x, formulas and examples 
for y ; table of real cut-off, values of real cut-off; formulas and examples 
for mean forward pressure; table of cut-off mean pressures; terminal 
pressures, formula, example and table; available heat in steam, in 
exhaust; compressed steam, interchangeable heat; high-speed engine- 
economy, limit of pressure, long stroke, overload, tests, leakage; 
theoretical efficiency of the steam-engine; formula, table; actual 
efficiency, formulas and examples; compression and back pressure, 
ratios, experiments; economy of high-pressure steam, diagrams; 
curves; most economical point of cut-off, diagram; experiments, four 
tables.171-189 


CHAPTER XIII 

Indicator and its work; Lippincott, high-pressure piston, reducing-wheel, 
setting and connections, slack spring, right and left indicator, meas¬ 
urement of card; planimeters, Amsler and Lippincott application; 
water used per horse-power hour by diagram, examples; high-compres¬ 
sion card; indicator-kinks, admission and terminal lines, wavy expan¬ 
sion-lines, diagrams of admission, compression, and terminal lines and 
their causes; exhaust-lines. 190-207 

CHAPTER XIV 

Steam-engine proportions; initial condensation formula, cylinder, diameters 
and ratios for compound engines, triple-expansion ratios; thickness 
of cylinders and heads, bolts, flanges, clearance, pipes, ports, valve- 
stem, piston, rings, rod, slides, pins, connecting-rod, caps, crank-pin, 
stresses, crank, rules; shaft, shaft-bearings, fly-wheels, rims and arms; 
speed, table of high-speed cylinder dimensions; table of slow-speed 
dimensions; composite pistons, segmental piston, Harris, Hewes & 
Phillips pistons; cross-heads, connecting-rod boxes, main bearings, 
fly-wheel construction, speed formula, weight, table of safe speeds, 
connecting-rod angle, three tables. 208-232 

CHAPTER XV 

Slide valve and valve gear; D valve, “over and under” running diagrams, 
valve setting, lap and lead, table of changes in lap, travel and lead, 
excessive compression, balanced valves, double ported and riding 
cover valves; independent cut-off valves, union and oscillating valves, 
gridiron valves; diagrams of lap, lead for slide valve cut-off, universal 
valve diagram for measurement; piston valve; Noye, hollow piston, 
Armington & Sims, Harrisburg types; slide valve gear, link motion 
gear, Stephenson and variable links, Marshall valve gear; reversing and 
floating valve gear, Walscheart valve gear, three cylinder and Brother- 



12 


CONTENTS 


PAGE 

hood engine valve gear, Wolf and triple expansion engine valve gear 
from single eccentric; Joy and Porter-Alien valve gear, Ball high speed 
tandem engine and valve gear, one table. 233-266 

CHAPTER XVI 

Corliss engine; illustrated type, valve movements and gear, single and 
double port valves, single eccentric valve gear, links and wrist plate; 
double eccentric wrist plates and valve gear; Fishkill, valve gear, 
diagrams of piston, crank and eccentric positions for cut-off; bell crank 
knock-off, Bass, Allis-Chalmers, Norclberg and trip valve gear; Sioux 
City, Scottdale and Watts-Campbell valve gear; governors and dash 
pots; Porter-Allen, Watertown, Lane & Bodley and Scottdale governors; 
fly wheel and pulley governors; Sweet, Fitchburg, shifting, rotating, 
dash pot and inertia governors; dash pots; Frick, and cup cylinder 
types; setting Corliss valve gears, wrist plate and rocker arm, wrist- 
plate positions; table of lap, lead and exhaust release; engines of the 
Hamilton, tandem compound and Cooper model; right and left hand 
engines, one table. 267-291 


CHAPTER XVII 

Compound engines; loss by cylinder condensation, table, value of com¬ 
pounding, table of water consumption in single and compound engines; 
experiments, 250 and 1,000 lbs. pressure; cylinder proportions, ta¬ 
ble, Harrisburg tandem compound, Vauclain compound and balanced 
engine, convertible and duplex compound, indicator diagrams, West- 
inghouse compound and diagram; diagrams of steam consumption and 
efficiency in compound and non-condensing engines; receivers with 
diagrams of pressures under variable conditions; reheating in receivers, 
three tables. 292-307 


CHAPTER XVIII 

Triple and quadruple expansion engines; increased efficiency by multi- 
expansion ; table, water consumption, test of high duty engine, diagram 
of pressures and temperatures; cylinder arrangement, cylinder propor¬ 
tions; engines of the Montana, Minnesota, novel marine engine, duplex 
piston triple expansion engine, one table. 308-316 

CHAPTER XIX 

The steam turbine; progress; Avery, De Laval and Parsons type described, 
bucket type, side nozle, steel disk, governing; diagram of efficiency, 
velocities, plan of De Laval turbine; Dow and Wilkinson turbine; multi¬ 
stage turbine; balancing pistons, form of blades; Westinghouse model, 
thrust bearings, admission ports, governing, steam puffs or vibrating 
inlet, pilot valve; friction, energy; table of efficiency tests, governor 


CONTENTS 


13 


PAGE 

and vibrating valve, diagram of puffs, Curtiss turbine, two stage, three 
stage, arrangement of nozles and blades, bucket segment, elevation and 
plan of 2,000 kilowatt turbine, slide valve regulation, four stage tur¬ 
bine, shaft step details, Rateau turbine, details of construction; 
Zoelly turbine, multistage impulse type, details of wheel and guide 
disks—rotary engine; Dake engine; starting and operation of large 
steam plants; comparison of times for starting to full sjneed, suggestions, 
one table.317-347 


CHAPTER XX 

Mechanical refrigeration engineering; principles of refrigeration; ammonia, 
anhydrous ammonia and its properties, compression system; table of 
properties, ammonia receiver, heat interchange, suction and discharge 
valves and their action, pressures of discharge and suction, diagram 
of principles, latent heat, test, liquid only that absorbs heat, com¬ 
pressor, three stages of refrigeration, complete refrigerating plant; De 
La Vergne and Frick cylinders, operation of the cylinder valves, surface 
condenser, double pipe condensers, diagram of ammonia compression; 
pointers on the operation of ammonia plants, pressures and economies, 
leaks, ice making, expansion valve, charging and starting, discharging 
air, signs of healthy working, one table. 348-371 

CHAPTER XXI 

The elevator and its working; direct cable, hydraulic piston elevators, pres¬ 
sure tank plant, high lift, multiple lift, three way valve, pilot valve, 
governor, gravity safety apparatus, automatic control, gravity wedge, 
details of cylinder and valves with names of parts; vamp, escalator, 
worm screw elevator, pump pressure regulator; air compressors and 
compressed air; diagrams of compression and expansion, two stage 
compression, compressors of the Clayton, Corliss, Bennett, Ingersol- 
Sergeant types, cylinders and valves, four stage compressor; blowing 
engines . 372-389 


CHAPTER XXII 

Cost of power; economyj table; estimate of cost of power plant, table; 
cost of steam per horse power, table, operative expenses; diagram of 
condensing plant, diagram of non-condensing plant; cost of distribu¬ 
tion, economical suggestions in the generation and use of steam, boilers, 
pressures, furnaces, feed water; types of engine, load, overload, losses; 
heating, three tables. 390-399 


CHAPTER XXIII 

The engineer and his duties, reference to special books, license, State and 
local, knocking and noises in the engine and their causes; don’ts for 
engineers and firemen; questions and answers .... 400-414 




14 


CONTENTS 


CONTENTS OF ELECTRICAL SECTION 


CHAPTER XXIV 

PAGE 

The dynamo and its regulation; operation of the dynamo; generation of 
E. M. F.; regulation of the dynamo; regulation with a rheostat; use of 
the commutator; regulation with a series wound dynamo; classification 
of dynamos; regulation in a shunt wound dynamo; regulation in a 
compound wound dynamo.419-429 

CHAPTER XXV 

Testing and motors; testing a dynamo for faults; causes of sparking; use of 
pole spray; short circuiting of commutator bars; dynamo fails to 
generate; cause of heat in the armature; heat in the commutator and 
brushes; radiating surface of coils and current carrying parts; types of 
motors in service; sparking in the motor; the back E. M. F. of a motor; 
humming and other noises in a motor. 430-440 


CHAPTER XXVI 

The switchboard and storage batteries; centers of distribution; classifica¬ 
tion of circuits; switchboard appliances; the ground detector; the light¬ 
ning arrester; storage batteries; types of storage batteries; difficulties 
with plates; efficiency of storage cells; the battery room . 441-453 

CHAPTER XXVII 

Lighting and lamps; electric lamps; the incandescent lamp; lamp efficien¬ 
cies; the Nernst lamp; the open arc; the flaming arc lamp; the en¬ 
closed arc; the mercury vapor lamp; vacuum tube lighting; electric 
light equipments; steam electric plants; net result in light from coal 
consumption; water power plants; gas engine electric plants . 454-477 


Questions and answers on Chapter XXIV 
Questions and answers on Chapter XXV 
Questions and answers on Chapter XXVI 
Questions and answers on Chapter XXVII 


. 465 
. 467 
. 470 
. 473 


CHAPTER I 


INTRODUCTION—HISTORICAL 


Steam lias been known as a source of power since the earliest 
historic time. 

It lifted the cover of the boiling-pot, even with a stone upon it, 
through the patriarchal ages, and later, with a tight-covered boiler, 
as designed by Heron of Alexandria, it became a source of power 
for motion in a rotary engine and 
in lifting a ball in a jet of steam, as 
here illustrated. Steam as a mo¬ 
tive force appears to have been 
well known to the priesthood and 
magicians of Egypt as described in 
their incantations for creating awe 
and fear in the ignorant and super¬ 
stitious people in that benighted 
age. There are reasons for believ¬ 
ing that the expansive force of the 
steam that was evolved in heat¬ 
ing the immense volumes of water 
for the hot baths at Rome, was employed to elevate and discharge 
the contents of the boilers; such being indicated by the investiga¬ 
tions at Pompeii. 

Steam was used in a feeble way by pressure and condensation 
for raising water during the first fifteen centuries of the Christian 
era, when its coming power only then began to enlighten the in¬ 
dustrial horizon as the dawn of its brilliant day four hundred years 
later. 

The experimental development of the properties and power of 

steam during the sixteenth century—the steam-played organ of 

Gerbert, the steam-gun of Leonardo da Vinci, the steam-boat of Blasco 

de Garay, the steam water-elevators of Baptist Porta—was a prog- 

15 



Force of the 
steam-jet. 



















16 


INTRODUCTION—HISTORICAL 


ress that to the acute mind of Roger Bacon opened a vista of the 
future which he expressed in the following prophetic words: 

“Men may construct for the wants of navigation such machines 
that the greatest vessels, directed by a single man, shall cut through 
the rivers and seas with more rapidity than if they were propelled by 
rowers; chariots may be constructed which, without horses, shall 
run with immeasurable speed. Men may conceive machines which 
could bear the diver, without danger, to the depth of the waters. 
Men could invent a multitude of other engines and useful instru¬ 
ments, such as bridges that shall span the broadest rivers without 
any intermediate support. Art has its thunders, more terrible than 
those of heaven. A small quantity of matter produces a horrible 
explosion, accompanied by a bright light; and this may be repeated 

so as to destroy a city or 
entire battalions.” 

Bacon was not a man 
to speak or write in this 
manner at random. His 
experiments led him to the 
conclusions he has thus 
recorded, for he was by 
far the most talented and 
indefatigable experimental 
philosopher of his age. 

The first application of 
steam under pressure to 
the propulsion of a boat 
was made by Blasco de Garay at Barcelona, Spain, in 1543, although 
a few experiments on the power to lift water by steam-pressure 
were made at an earlier date and continued into the seventeenth 
century by De Caus, Branca, and the Marquis of Worcester. Dr. 
Denys Papin, in 1695, was probably the first to use the moving 
piston and the walking-beam on a steam-boat in the river Seine in 
France. To Dr. Papin may be attributed the origin of the steam- 
engine for power use. Steam under high pressure was used by him 
in the “Papin digester,” a name surviving at the present time. 
Savory, a contemporary of Papin, in England, built water-raising 



Destruction of Denys Papin’s steam-boat in 1695, 
by the bargemen of the Seine (by Figuier). 






















INTRODUCTION—HISTORICAL 


17 


engines by direct action of steam and a vacuum; but little progress 
was made until Newcomen brought out the piston and walking- 
beam engine, for deep-well 
and mine pumping, in 1705; 
from which time there was 
but little improvement for a 
half century, until the time of 
James Watt, although Leu- 
pold, in 1720, invented a two- 
cylinder, single-acting piston- 
engine, moved by steam- 
pressure and exhausting into 
the atmosphere. 

James Watt commenced 
experimental work on the 
steam-engine about 1761, 
making rapid progress in improvements of single-acting types, and 
by closing the top of the cylinder for the double-acting effect. The 

water-spray or separate con¬ 
denser and air-pump, the atmos¬ 
pheric siphon. condenser, the 
steam-jacketed cylinder, the par¬ 
allel-motion crank, the fly-wheel, 
and the fly-ball governor were 
invented or applied by Watt 
previous to 1782, at which time 
he received a patent for the cut¬ 
off for using steam expansively 
in the cylinder. Thus it seems 
that the main features of the 
modern steam-engine were in 
use at the close of the eighteenth 
century. 

Efforts to apply this pioneer 
of motive power to boats were 
made during the early part of 
the eighteenth century, and later in the century to vehicles, with 
a few improvements in its action and economy. 



Watt’s single-acting condensing-engine. 




























































































































































































































































































18 


INTRODUCTION—HISTORICAL 


The compound steam-engine was patented in 1781 by Horn blower, 
in England, from which time steam-pressure as a practical power 
became progressive. 

During the first century of the usefulness of steam little or no 
pressure was used in its operation for power, and not until the close 
of the eighteenth century was the then-called high-pressure engine 
brought into use, when 25 pounds per square inch was considered 
high pressure, and during the first half of the nineteenth century 
50 pounds was named as high pressure, although much higher pres¬ 
sures were used for special purposes. In 1840 the Perkins steam- 
gun was operated by the author in New York City, with a steam- 
pressure of 1,000 pounds per square inch. It made wafers of bullets 
against an iron target; but the steam-gun did not prove practicable. 
At the dawn of the nineteenth century patents upon the principles 
of the application of high-pressure steam to engines were held by 
Trevethick and Vivian, in England, which were a menace to progress 
by contemporaries; yet progress in design and application to the 
propulsion of boats and the locomotive began the infancy of its 
future career. 

In the hands of Stevens and Fulton in the United States, and of 
Bell, Dodd, and others in England, steam navigation made a won¬ 
derful stride during the first half of the cenftiry; while the stationary 
engine plodded along seemingly in the rut of the slide-valve move¬ 
ment and slow speed. The cylindrical multitubular boiler became the 
leading type for the economical generation of steam and, with the 
internal furnace, the fixed type for marine and locomotive service. 

The duty of a motive power is measured by the foot-pounds work 
produced per pound of a given heat-unit capacity of the fuel, or the 
initiative value of the power-producer. The progress of improve¬ 
ment during the first half of the nineteenth century was registered 
by the improvement in pumping service, which gradually advanced 
from a duty of 20,000,000 at the beginning of the century, to 108,- 
000,000 in 1842, per bushel of 94 pounds Welsh coal, or equivalent 
to 1,148,936 foot-pounds per pound of coal; all due to improvements 
in boiler and engine design, compounding, and more perfect condens¬ 
ing effect. 

During the latter half of the nineteenth century the duty in pump¬ 
ing-engines of the larger size had been raised to above 1,600,000 


INTRODUCTION—HISTORICAL 


19 


foot-pounds per pound of coal yielding 10,000 heat-units from the 
boiler in steam. This advance was largely due to increased boiler- 
pressure, 160 to 185 pounds gauge, and triple-expansion engines, giv¬ 
ing efficiencies of above 21 per cent. 

In this period the relative proportions of cylinder size and stroke 
have been changed to more nearly equalize the volume and wall sur¬ 
face, which means short stroke and larger diameter; types of the high¬ 
speed, tandem compound engines of to-day. From the middle of the 
century on, improvements in valve-gear continued to be made; the 
poppet-valve became established for engines in marine and river 



Hornblower’s compound pumping-engine. 


service, and steam and exhaust lap and lead became an established 
principle in engines of the slide-valve and other types. 

The latter half of the nineteenth century was a marked period in 
developing the efficiency and usefulness of the steam-engine. 

Compression of the exhaust at the terminal of the piston-stroke 
became a fixed principle in design for smooth running in high-speed 
engines, although its efficiency is still a matter of discussion. 

The quick and controllable valve-movement came with the Corliss 
type and established an advanced efficiency in the development of 
steam-power, and with increased steam-pressure, short cut-off and 
compounding have brought the coal value of a horse-power below 
1 pound per hour. 




































































































































































































































































































20 


INTRODUCTION—HISTORICAL 


The quadruple-expansion system seems to have reached a point 
that bars further progress in that direction; but with the opening 
of the twentieth century the long-dormant rotary principle received a 
new and practical impulse in the successful instalment of the steam- 
turbine; although not showing as yet an advance in steam efficiency, 
it fills a long-felt want for compactness and speed for marine and 
electric requirement, and thus has become the means for making a 
great advance in the usefulness of steam-power. 

The principle of Heron’s engine was the utilization of the reaction 
caused by the escape of steam from jets protruding tangentially from 
a hollow globe, this reaction causing the rotation of the globe. 

More than seventeen hundred years later—in 1629—Giovanni 
Branca, an Italian inventor, devised an impact steam-turbine em¬ 
bodying the same principles as the familiar impact water-wheel of to¬ 
day, except that a jet of steam instead of water impinged upon the 
vanes of the paddle-wheel and caused it to revolve. The advent of 
the reciprocating steam-engine early in the eighteenth century di¬ 
verted attention from the earlier attempts to perfect a rotating engine, 
and it was not until near the end of the nineteenth century that the 
steam-turbine again made its appearance as a commercial possibility. 
De Laval, in Sweden, in 1883, and Parsons, in England, in 1884, con¬ 
structed successfully operating steam-turbines, and a continuous 
process of development and improvement has demonstrated the prac¬ 
ticability and commercial value of this form of motor in two distinct 
types, obtaining efficiencies which rank with the best reciprocating 
engines. The performance of the steam-turbine, with the several 
very important advantages, justifies the belief that the field held 
for more than a century by the reciprocating engine of Watt is likely 
to be seriously invaded by this modern application of the earliest 
principles of steam-engineering, which is made possible by the better 
materials and workmanship and the more intelligent skill now avail¬ 
able. 

We cannot improve on the expressions of Prof. R. H. Thurston 
in regard to the progress in the realization of the practical possibilities 
and economics from the power of steam: 

“The end of the nineteenth century is that of one which will always 
remain preeminent in history as the age in which the steam-engine 


INTRODUCTION—HISTORICAL 


21 


took shape in the hands of Watt and Sickles and Corliss and Greene, 
of Porter, and their successors, and thus brought in the factory 
system and all our modern methods of production, in the improve¬ 
ment of the condition of the people, and in all the material advance¬ 
ment in the industrial arts, which has made the century distinctively 
one of supremacy of the mechanic arts. The close of the century 
finds the steam-engine, though threatened with displacement by 
other motors, in the view of many writers, nevertheless the great 
motor of the age. Substantially all of the power employed by the 
civilized world is supplied by this great invention—congeries of in¬ 
ventions, rather—the product of a series of improvements, of an 
evolution effected during the hundred years or more just past. The 
limit to be possibly attained in its development and perfection will 
always remain a subject of intense interest to the profession and to 
the world. 

“Reviewing the history of the growth of this form of steam- 
engine, it will be seen that its progress has illustrated that of the 
machine in all its forms, and that the steam pumping-engine gives 
the engineer a record of greater extent and of more representative 
character, as exemplifying the evolution of the machine, than does 
any other type. r 

“The twentieth century will very probably see a change in the 
curve of our lines, if not, in some respects, a decided halt or a reversed 
curvature, and it is perhaps even more probable that the field of the 
steam-engine will become greatly restricted by the introduction of 
other heat-motors, as well as by the general employment of electricity 
as a medium of extensive power-distribution from hydraulic and 
pneumatic prime movers. 

“The steam-engine has now been so far perfected, and the prac¬ 
tical limits of pressure are coming to be so nearly approached by 
steam-boiler constructors and users, that but little more can be ex T 
pec ted of the designer; and even with the costlier types of engine, 
practically justifiable with exceptionally high costs of fuel, uninter¬ 
rupted working, and low values of money, as in some instances with 
the steam pumping-engine, commercially practicable progress seems 
likely henceforth to prove very slow. These costly types of engine 
must necessarily have a comparatively narrow field. With the com¬ 
mon case of moderate cost of fuel, intermittent duty, comparatively 


22 


INTRODUCTION—HISTORICAL 


high value of money in the business, or absolute scarcity with the buyer, 
gains seem likely hereafter to be rather in the direction of cheapened 
methods of construction and simplification of design.” 

The progress in the economy of fuel by increased steam-pressure 
in marine service during the past three-quarters of a century has 
been most marvellous, and, together with the improvements in con¬ 
struction of both engines and boilers, multiple expansion with sur¬ 
face condensation, has resulted in the saving of about 900 per cent, 

■ 012imi.ii.i Caloric Engine 

Direct Acting Pump 

,077 Early Slide Valve 

.12 -. Automatic High Speed 

Simple Condensing 

1 Q ■■■HHMMnMnHHniHsiyBMnMHBmnnMi Steam Turbine 


.18 


Corliss Condensing 


.19 


Compound Condensing 


215 i n .■■■i.i m ■—«.— Triple Condensing 
.23 Quadruple 


.30 


Explosive Motor 
Diagram of progress. 


reducing the old-time consumption of about 10 pounds to nearly 1 
pound of coal per indicated horse-power. The progress in the rise 
of steam-pressure and consumption of coal per indicated horse-power, 
with few exceptions, is shown approximately in the following table: 


Year. 

Steam-pressure. 


Coal per I. 

H. P. 


1830. 

13 

to 

14 

lbs. 

gauge 

9 

to 

10 

lbs. 

per 

hour 

1840. 

18 

U 

25 

U 

U 

54 

(C 

6 

U 

U 

U 

1850. 

24 

U 

40 

U 

a 

4 

u 

5 

u 

u 

u 

1860. 

40 

u 

50 

(( 

a 

3 

cc 


u 

u 

a 

1870. 

50 

u 

75 

(C 

u 

91 
w 2 

u 

3 

u 

(C 

u 

1880. 

75 

(C 

100 

u 

u 

91 
" 4 

u 

2f 

(( 

u 

u 

1890. 

125 

u 

150 

u 

u 

u 

u 

2 

u 

u 

a 

1900. 

160 

u 

200 

u 

u 

If 

u 

1 - a - 
1 1 0 

u 

u 

a 




























INTRODUCTION—HISTORICAL 


23 


In stationary service the steam-pressures have been greater than 
above stated in the earlier years, and the coal-saving has been im¬ 
proved in the most modern designs for the greatest possible expan¬ 
sion and mechanical efficiency for high-power service. The diagram of 
progress shows, in percentages, the approximate progress of thermal 
efficiency in different types and designs of engines for motive power. 

The rapid progress recently made in steam-turbine design has 
given it a leading position in its special field of usefulness. Speed 
with power is a rare combination for useful effect in electrical gen¬ 
eration, as well as in marine propulsion, in which both have made 
new records in their respective lines of practical operation. 

We can scarcely realize the fact of the startling changes in the 
industrial and financial values in all the civilized world that have 
occurred within our memory and that have been due to education 
and its bearing upon this inventive age, and in which steam, with its 
work, with been one of the principal factors. 


CHAPTER II 


STEAM AND ITS PROPERTIES 

Steam, the vapor from water, is, like water, the product of a com¬ 
bination of the so-called permanent gases, hydrogen and oxygen, 
in the proportion by weight to one of the former to eight of the latter 
gas, and by volume one of hydrogen to two of oxygen. 

This combination of these gases to form water, or its vapor, and 
steam is permanent up to a temperature to or above 2,000° F., when 
dissociation takes place from heat alone; but at much lower tempera¬ 
tures when in contact with ignited carbon in coal and other fuels; 
the oxygen combining with the carbon forming carbonic acid, CO 2 , 
and carbonic oxide gas, CO, setting hydrogen free, and thus forming 
hydrocarbon compounds. 

Water vaporizes at temperatures below its freezing-point, and as 
ice its vapor-pressure becomes zero at about —101° F. At 32° F. the 
vapor of water exceeds 208,000 volumes at as near a vacuum as 
practically possible, with an increasing density to about 20,000 
volumes at 1 pound absolute pressure and temperature of 102° F., 
and to 2,361 volumes at 10 pounds absolute pressure and temperature 
of 193° F. As the temperature of the boiling-point is neared its den¬ 
sity increases, and under atmospheric pressure (14.7 absolute), at 
212° F. its vapor capacity is 1,646 volumes, or 26.36 cubic feet per 
pound of steam, weighing .03794 pound per cubic foot. 

Steam when blown into the atmosphere expands to atmospheric 
pressure with a temperature of 212° F., and has but one-half the density 
of the atmosphere; hence it rises quickly, and, mixing with the air, is 
cooled, and by condensation into vesicles becomes a cloud. Pure 
steam is perfectly transparent, and so appears when looking through 
a jet close to the nozzle. The liberation of steam and vapor con¬ 
tinues below atmospheric pressure in increasing volume per pound 
of water or vapor with a decreasing temperature of its boiling-point 
and absolute pressure. This property of evaporation at negative 

pressures and low temperatures has become a most valuable adjunct 
24 


STEAM AND ITS PROPERTIES 


25 


of industrial work, indispensable in the modern methods of sugar 
and salt manufacture, and largely in use in the so-called vacuum¬ 
drying of various kinds of material and the condensation of liquids. 

The following tables give the volume of 1 pound of water in 
vapor at various temperatures and pressures from and below the 
boiling-point of water at atmospheric pressure, and the elastic force 
of vapor at various temperatures. 


Table I.—Boiling and Vaporizing Temperatures of Water, at and Below 
Atmospheric Pressure, with Pressures and the Volume of 1 Pound 
of Vapor. (Claudel.) 


Tempera¬ 

ture, 

Fahren¬ 

heit. 

Pressure. 

Volume of 

1 pound, 
cubic feet. 

Mercury, 

inches. 

Per 

square 

inch, 

pounds. 

212° 

29.92 

14.70 

27.2 

210 

28.75 

14.12 

28.2 

205 

25.99 

12.77 

31.0 

200 

23.46 

11.52 

34.1 

195 

21.14 

10.38 

37.6 

190 

19.00 

9.33 

41.5 

185 

17.04 

8.37 

45.9 

180 

15.29 

7.51 

50.8 

175 

13.65 

6.71 

56.4 

170 

12.18 

5.98 

62.4 

165 

10.84 

5.33 

69.8 

160 

9.63 

4.73 

75.0 

155 

8.53 

4.19 

87.3 

150 

7.55 

3.71 

97.8 

145 

6.66 

3.27 

110.0 

140 

5.86 

2.88 

124.1 

135 

5.17 

2.54 

140.1 

130 

4.51 

2.21 

158.7 

125 

3.93 

1.93 

180.5 


Tempera¬ 

ture, 

Fahren¬ 

heit. 

Pressure. 

Volume of 

1 pound, 
cubic feet. 

Mercury, 

inches. 

Per 

square 

inch, 

pounds. 

120° 

3.43 

1.68 

204.9 

115 

2.97 

1.46 

234.7 

110 

2.57 

1.27 

268.1 

105 

2.23 

1.09 

307.7 

100 

1.91 

.94 

353.4 

95 

1.64 

.81 

408.2 

90 

1.41 

.69 

471.7 

85 

1.20 

.59 

549.5 

80 

1.02 

.50 

641.0 

. 75 

.87 

.43 

746.3 

70 

.73 

.36 

877.2 

65 

.62 

.30 

1031.0 

60 

.51 

.25 

1220.0 

55 

.42 

.21 

1429.0 

50 

.36 

.18 

1695.0 

45 

.30 

.15 

2041.0 

40 

.25 

.12 

2439.0 

35 

.20 

.10 

2941.0 

32 

.18 

.09 

3226.0 


Table II.—Elastic Force of Vapor of Water at Temperatures from 0 to 
212° F., and Atmospheric Pressure of 14.7 Pounds. Barometer, 29.92. 


Tempera¬ 

ture, 

Fahren¬ 

heit. 

Elastic 

force, 

inches, 

mercury. 

Tempera¬ 

ture, 

Fahren¬ 

heit. 

Elastic 

force, 

inches, 

mercury. 

Tempera¬ 

ture, 

Fahren¬ 

heit. 

Elastic 

force, 

inches, 

mercury. 

Tempera¬ 

ture, 

F ahren- 
heit. 

Elastic 

force, 

inches, 

mercury. 

0° 

.044 

62° 

.556 

122° 

3.621 

182° 

15.960 

12 

.074 . 

72 

.785 

132 

4.752 

192 

19.828 

22 

.118 

82 

1.092 

142 

6.165 

202 

24.450 

32 

.181 

92 

1.501 

152 

7.930 

212 

29.921 

42 

.267 

102 

2.036 

162 

10.099 



52 

.388 

112 

2.731 

172 

12.758 



















































26 


STEAM AND ITS PROPERTIES 


Table II will be found convenient for aiding the formulas for 
computing the evaporation in Table IV for other air temperatures 
and humidities as stated in the heading of that table. 


Table III. —Boiling-Point of Pure Water at Pressures Below the Absolute 
Atmospheric Pressure of 14.7 Pounds per Square Inch. 


Barometer, 

inches. 

Absolute 

gauge- 

pressure, 

pounds. 

Boiling-point, 

Fahrenheit. 

Barometer, 

inches. 

Absolute 

gauge- 

pressure, 

pounds. 

Boiling-point, 

Fahrenheit. 

29.92 

14.70 

212° 

20.25 

9.94 

193° 

29.33 

14.40 

211 

19.82 

9.73 

192 

28.75 

14.11 

210 

19.41 

9.53 

191 

28.18 

13.83 

209 

19.00 

9.33 

190 

27.61 

13.55 

208 

18.59 

9.12 

189 

27.06 

13.28 

207 

18.19 

8.93 

188 

26.52 

13.02 

206 

17.81 

8.74 

187 

25.99 

12.76 

205 

17.42 

8.55 

186 

25.46 

12.50 

204 

17.05 

8.36 

185 

24.94 

12.23 

203 

16.31 

8.00 

182 

24.44 

12.00 

202 

14.27 

7.00 

174 

23.94 

11.75 

201 

12.23 

6.00 

166 

23.45 

11.51 

200 

10.19 

5.00 

157 

22.97 

11.28 

199 

8.16 

4.00 

147 

22.49 

11.04 

198 

6.09 

3.00 

135 

22.03 

10.81 

197 

4.07 

2.00 

123 

21.57 

10.59 

196 

2.04 

1.00 

109 

21.13 

10.37 

195 

0.00 

0.00 

98.7 

20.68 

10.15 

194 





Pure water is said to boil in as near a perfect vacuum as its rising va¬ 
por by its rapid expansion will allow, at a temperature of 98° F. This 
was indicated by the double-bulb vacuum-tube in Franklin’s experi¬ 
ment. The author has seen a carafe, partly filled with water at 50° F., 
placed under a nearly perfect vacuum made by the pump of a vacuum 
ice-making machine; the water boiled violently for a few seconds, the 
agitation not ceasing until ice began to form and became solid in a few 
minutes. The violent agitation was caused by the liberation of air. 

Water holding salts and other substances in solution has its boiling 
temperature raised above 212° F., and thus becomes a valuable means 
of transmitting heat for boiling or concentrating liquids at open-air 
exposures and temperatures slightly above the boiling-point of water. 

The following are convenient solutions for limiting temperatures in 
double-jacket kettles: 

Common salt, for any temperature up to its point of saturation, 
227° F. 























STEAM AND ITS PROPERTIES 


27 


Carbonate of soda, up to 220° F. 

Nitrate of potash, up to 240° F. 

Nitrate of soda, up to 250° F. 

Carbonate of potash, up to 275° F. 

Acetate of potash, up to 336° F. 

The operation of chemical and industrial processes with heat- 
above the boiling-point of water is a most important point for ob¬ 
taining uniform results in the vast chemical, pharmaceutical, and 
provision-canning industries of this age. When absolute uniformity 
of temperature at a few degrees above the boiling-point of water is 
required, there is no more safe and reliable method than by the use of 
one of the above-named salts in part, as a bath or a saturated solution 
in open single-jacketed kettles heated by fire, or in double-jacketed 
kettles heated by steam, in which the boiling temperature of the 
heat-transmitting medium can always be under observation with a 
thermometer. By the direct heat of steam, as in the usual method 
of taking steam from a high-pressure factory-boiler, the pressure and 
temperature are often regulated by guess, a safety-valve, or a regu¬ 
lator; but these have their troubles and dangers. 

Table IV. —Approximate Heat Required for Evaporating Water at and 
Below the Boiling-Point, from Open Vessels in Calm Air at a Temper¬ 
ature OF 52° F. AND 86 PER CENT HUMIDITY. (Box.) 


Tem¬ 
perature 
of water. 

Water evapo¬ 
rated PER SQUARE 
FOOT PER HOUR 

IN CALM AIR. 

Time to 
evapo¬ 
rate 

1 pound 
of water 
in hours. 

Heat 
lost by 
radia¬ 
tion 
from 
surface. 
Units 
per hour. 

Heat 
carried 
off by 
air. 
Units. 

Latent 
heat of 
vapor¬ 
ization. 
Units. 

Total 
heat to 
evapo¬ 
rate 

I pound 
of water. 
Units. 

Total 
heat per 
square 
foot per 
hour. 
Units. 

Cubic 
feet of 
air at 
52° F. 
to evap¬ 
orate 1 
pound 
of 

water. 

Pounds. 

Depth in 
inches. 

62° 

.0143 

.00275 

70.0 

11.3 

888 

1,071 

2,750 

39 

4,807 

72 

.0343 

.0066 

29.2 

23.4 

753 

1,064 

2,500 

86 

2,036 

82 

.0615 

.0118 

16.3 

35.2 

649 

1,057 

2,280 

140 

1,160 

92 

.0986 

.0190 

10.2 

47.0 

555 

1,050 

2,080 

204 

747 

102 

.150 

.0288 

6.67 

62.7 

449 

1,043 

1,910 

287 

486 

112 

.221 

.0425 

4.52 

76.7 

387 

1,036 

1,770 

392 

350 

122 

.315 

. 0606 

3.13 

91.2 

326 

1,029 

1,640 

524 

253 

132 

.454 

.0873 

2.20 

106.8 

278 

1,022 

1,535 

698 

184 

142 

.634 

1 oo 

1.58 

122.5 

241 

1,015 

1,450 

918 

146 

152 

.871 

.168 

1.15 

141.1 

206 

1,008 

1,376 

1,197 

112 

162 

1.18 

.227 

.848 

156.4 

193 

1,000 

1,326 

1,564 

95 

172 

1.57 

.302 

.637 

175.5 

179 

993 

1,284 

2,016 

81 

182 

2.06 

.396 

.485 

193.2 

168 

986 

1,248 

2,573 

70 

192 

2.66 

.512 

.374 

215.7 

164 

979 

1,224 

3,268 

64 

202 

3.41 

.656 

.293 

237.7 

161 

972 

1,203 

4,106 

58 

212 

4.32 

.831 

.232 

257.0 

160 

966 

1,186 

5,112 

54 




























28 


STEAM AND ITS PROPERTIES 


The above table was derived from Regnault’s experiments and 
verified by Box practically as to quantity, depth, and time. The 
formula for evaporation is (1) E = (243 + (3.7 Xt) X(V —v), iii which 
E = evaporation per square foot per hour in grains; t = temperature 
of the water; V = elastic force of vapor at temperature t; v = force of 
vapor in air due to its percentage of humidity; or, by the table, II. 
V = .388 for 52° and v = .388 X .86 = .334. For example, for water 62°, 
air 52°, and humidity .86, 

(1) E = (243 + (3.7 X 62) X (.556 -334) = 472.4 X .222 = 104.8 grains, and 
104 8 

7 000-- 0149 P ounc ^ theoretical evaporation per hour. 

The second and third columns in the table represent the experi¬ 
mental values. 


The employment of a vacuum in boiling and evaporating 
water in the art of food preparation has become an important 
item in the industrial economy of these 
times. Among the many devices of the 
vacuum system of evaporation we il¬ 
lustrate the principles of its operation 
in an apparatus (shown in Fig. 9) for 
obtaining fresh water from salt water 




by the use of steam as the heating medium, which represents a 
fresh-water still: 



































































































































STEAM AND ITS PROPERTIES 


29 


The chamber is kept supplied half full of salt water and kept be¬ 
low saturation by blowing off. The vapor is drawn off through the 
perforated pipe at the top through a condenser by the vacuum-pump. 



The boiling temperature of the salt water of the ocean is about 
153° F., with a 26-inch vacuum. The condensed steam from the coils 
is saved and fed to the boilers. The condensed vapor from the salt 

















































































































































































































































































































30 


STEAM AND ITS PROPERTIES 


water is aerated and cooled for drinking. For the distillation of 
water for ice-making this principle seems to be the most economical 
conserver of heat known. By devices of double and triple effect, 
with coal at New York prices, pure distilled water can be produced 
at a cost of about 75 cents a thousand gallons; and when using the 
exhaust steam from a power-plant, the cost of producing a limited 
amount of distilled and aerated water is a mere nominal item. 

The manufacture of salt by the vacuum process is becoming an 
important item in this industry. In Fig. 10 is shown the initial 
evaporating section of a triple-effect system consisting of three evap¬ 
orating-pans set side by side with their terminal connected with the 
condenser and air-pump. 

In this salt-making apparatus A is the vapor section, B the 
heating section, consisting of a series of vertical tubes connected 
from the boiler or the exhaust from an engine by the pipe E. In a 
triple-effect system the vapor-chamber A is connected with the 
heating section B of the next effect, and so on to the third effect, 
which has its chamber connected to the condenser and air-pump. G 
is the brine-inlet and C the crystallizing-chamber, from which the 
crystallized salt is discharged into the settling-chamber D through a 
slide-valve or gate. This is a continuous system and needs no sus¬ 
pension of the evaporating effect in each of the three sections as a 
triple effect. 

In Fig. 11 is shown the elevation of one section of a sugar-boiling 
plant, operated on the dry system of evaporation, in which the vapor 
enters a jet-condenser and the condensed steam and water pass 
down a stand-pipe or siphon by gravity to a cistern 35 feet below the 
condenser, which seals the exit-pipe against atmospheric pressure. 
The air-pumps are only required to keep the system relieved of air 
and uncondensed vapor. 

In this type of evaporator a series of copper coils enters the evap¬ 
orating-pan from a header, and, circling around the inside, gives 
sufficient surface for the work of evaporation. Sometimes a surface 
condenser is used with a second pump for discharging the water of 
condensation. 


GENERATION OF STEAM 


FURNACES AND THEIR ADJUNCTS 

The economical generation of steam is becoming one of the most 
essential features in the world of engineering design for the produc¬ 
tion of power. The vast progress in manufacturing and producing 
industries of this age and their competitive relations not only require 
the utmost economy in the production of power, but even the fuel 
for power has its limit of production and its liability to increased 
cost; this serves as a warning to harbor our resources of the present 
for future emergencies. 

The generator of steam and its power-developing agent, the 
steam-engine, have had a slow growth in development during the 
progressing ages of civilization, and only during the past century of 
scientific research have the principles for the economical application 
of this vast power been mathematically realized and applied. 

The greatest economy in the production of steam begins at 
the furnace-door—the method of firing by which the most perfect 
combustion is produced and every atom of heat-producing fuel 
is consumed for the evolution of the highest temperature in the 
furnace. 

Of the fuels in use for generating steam, anthracite and bitu¬ 
minous coal stand at the head, in accordance with their respective 
qualities in the carbon element. Wood, saw-mill refuse, lignite, peat, 
planing-mill shavings, bagasse, tan-bark, are in use with appropriate 
furnaces; while crude petroleum is gaining a leading fuel value in 
districts where it is cheaper than coal and in countries having small 
coal resources. The anthracite coals vary from 83 to 90 per cent in 
fixed carbon, with the volatile matter generally varying inversely 
to the fixed carbon, so that the total combustible averages about 90 
per cent. With bituminous coals the volatile element is very large, 


32 GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 

and with this perfectly consumed, its steam-making value is fully 
equal to anthracite per pound of combustible. 

The steaming value of anthracite coal varies somewhat with its 
size for a given weight, as the ash products in merchantable coals 
vary from about 5J per cent in broken and egg size to above 16 per 
cent in pea and buckwheat sizes; yet with properly designed grates for 
burning the small sizes they are the most economical steam-makers 
from their low price. 

Wood for steam-making is but little used, and is mostly derived 
from the waste in lumber-making, such as slabs, sawdust, mill- 
shavings, etc. Cord-wood, such as used for steam-making, contains 
about 55 per cent of its weight in combustible, combined with about 
40 per cent of oxygen, which adds nothing to its heat-producing 
value, and only makes the wood highly inflammable. An average 
of 21 pounds of dry wood is equal to 1 pound of good anthracite 
or bituminous coal. In the following table are given the average 
weight of air-dried cord-wood per cord and its equivalent weight in 
anthracite or bituminous coal: 


Table V.— Average Weight of Air-Dried Cord-Wood and Its Equivalent 

Weight in Coal. 


Kind. 


Pounds per cord. 


Pounds of coal. 


Shell-bark hickory. 

White oak. 

Red-heart hickory. 

Beach, red and black oak. 

Southern pine (pitch-pine). 

Maple. 

Virginia pine. 

Spruce and New Jersey pine.... 
White and yellow pine, hemlock 


4,470 

1,987 

3,821 

1,700 

3,705 

1,646 

3,250 

1,444 

3,375 

1,500 

2,878 

1,279 

2,690 

1,151 

2,137 

949 

1,900 

844 


Lignite, or brown coal, is of recent geological formation. When 
dry it ignites easily and burns freely, and as a steam-producing fuel 
is between wood and coal as to bulk. Its specific gravity is from 1.10 
to 1.25. It is used in many localities where it can be obtained at a 
less cost per combustible weight than coal or wood. 

Peat or turf is of little value for steam-making. In a few locali¬ 
ties, and in Germany, it is briquetted by drying and compressing, in 
which form it has been in use for some time, burning much like wood. 



















GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 33 

Coke is but little used for steam-making; it lias a higher carbon 
value per pound than coal and makes a hot, clear fire. 

Sawdust and shavings are used in wood-working mills for steam- 
fuel, more for the economy of disposing of them than for their steam¬ 
making value. 

Bagasse and straw in the sugar and agricultural districts are 
used for steam-making as a means of disposing of by-products, and 
with bagasse fired in special furnaces under the long cylinder boilers 
set for this purpose, it seems to be a measure of real economy in turning 
the immense by-product of a sugar plantation to the best account. 

The use of petroleum for steam-making has made a vast stride 
in late years, and especially in and near the oil districts, where its 
price competes with that of coal. 

The oil constituents vary somewhat in different localities, with an 
average of carbon .86, hydrogen .13, oxygen .01, with their specific 
gravity varying from .80 to .94 and weighing from 6.6 to 7.6 pounds 
per gallon. The total heat of combustion varies from 19,000 to 
22,000 heat-units per pound, with a theoretical evaporative power 
of from 19.6 to 22.7 pounds of water per pound of oil. 

From comparison of the constituents of coal and petroleum the 
heating value of the oil is about 1J times that of the coal; but in 
practice the heating value of oil has been found to be equal to twice 
the value of coal per pound in evaporating power. This has been 
accounted for by the more complete combustion of the liquid fuel 
and freedom of the tubes from soot and ashes. The admission of 
air being under complete control with the fine atomizing of the oil, 
brings the air and fuel into immediate and perfect contact with but a 
very small excess of air; while with coal much of the loss by com¬ 
bustion is due to excess of air. Another point in favor of oil fuel is the 
saving in banked fires and the convenience of instantaneous starting 
and extinguishing the furnace fire; while, with a well-constructed 
furnace and boiler-setting, the boiler will retain sufficient heat during 
the night for a quick morning start. 

Natural gas, which is largely in use in the gas districts, with a 
heating capacity of from 900 to 1,200 thermal units per cubic foot, 
is a matter for economical consideration as to its cost per 1,000 
cubic feet. 


34 GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 

Mr. J. M. Whitham, who has investigated the natural-gas question, 
has summarized the subject in the following brief paragraphs: 

1. In regard to burners, there is but little advantage possessed 
by one burner over another. 

2. As good economy is made with a blue as with a white or straw 
flame, and no better. 

3. Greater capacity may be made with a straw-white than with a 
blue flame. 

4. An efficiency as high as from 72 to 75 per cent in the use of 
gas is seldom obtained under the most expert conditions. 

5. The “ air for dilution” is greater with gas than with coal, so 
that possible coal efficiencies are impossible with gas. 

6. Don’t expect, in good commercial practice, to get a boiler horse¬ 
power on less than from 43 to 45 cubic feet of natural gas, the same 
being referred to 60° F. and 4-ounce pressure above a barometer of 
29.92 inches. 

7. Fuel costs are the same under best conditions with natural gas 
at 10 cents per 1,000 cubic feet and semibituminous coal at $2.87 
per 2,240 pounds. This is based on 3.5 pounds of wet coal being 
used per boiler horse-power per hour, or 45 cubic feet of natural gas. 

8. Expressed otherwise, a long ton of semibituminous coal is the 
equivalent of 28,700 cubic feet of natural gas; while a short ton of 
such coal is the commercial equivalent of 25,625 cubic feet. 

9. As compared with hand-firing with coal in a plant of 1,500 
boiler horse-power output, coal being $2 per 2,240 pounds—consider¬ 
ing labor-saving by the use of gas—natural gas should sell for about 
10 cents per 1,000 cubic feet. 

The largest constituent of natural gas is marsh-gas, CH 4 , varying 
from 96 to 67 per cent; the next is hydrogen, H, varying from 22 to 
6 per cent; the balance being ethane, C 2 H 4 , from 18 to 5 per cent, 
with traces of CO and C0 2 and free oxygen and nitrogen. 

The economy of combustion in a boiler furnace is so much a 
matter of experience in the management of the fire and the relative 
volume of air allowed to pass through the furnace that is not required 
for combustion, and so much depends upon good practice derived 
from experience and good judgment in the handling of a fire, there 
is but little of value to be said in regard to its details. 


GENERATION OF 


STEAM—FURNACES AND THEIR ADJUNCTS 


35 


In the disposition of the fuel elements by combustion, 1 pound of 
carbon requires 2.66 pounds of oxygen or 12 pounds of air or 162 cubic 
feet at boiler-room temperature for complete combustion, and having 
a heat value of 14,600 thermal units. 

One pound of hydrogen requires 8 pounds of oxygen, 36J pounds 
of air, 490 cubic feet, for complete combustion, with a heating value 
of 62,000 thermal units. Thus, for example, for anthracite coal with 
carbon .91, hydrogen .028 per cent—162x.91 = 147i cubic feet of air 
for the carbon, and 490X.028 = 13| cubic feet of air for the hydrogen, 
or 161 cubic feet of air per pound of coal for perfect combustion. 

In practice perfect combustion cannot be obtained with less than 
from 1J to 2 times the quantity of air actually needed for perfect 
combustion. 

The necessities for feeding the fire with open doors, and the faulty 
practice of letting too much air into the furnace for the consumption 
of the gaseous distillates above the fire, and for smoke consumption 
of bituminous fires, are serious drawbacks to the ultimate heat pro¬ 
duction of the furnace. 


The volume of gases passing to the chimney is largely increased 
by excess of air to the furnace above the actual requirement for com¬ 
bustion, which for each pound of carbon in the coal and 50 per cent 
excess of air the products of combustion will increase in volume 
nearly in proportion to the excess of air, or to 18 pounds of air; and 
as the gases are expanded to nearly double their initial volume at the 
chimney temperature of 500°, it indicates a chimney volume of about 
500 cubic feet of gases for each pound of carbon consumed in the 
furnace. Assuming that there is no air passing up the chimney other 
than that which has passed through the fire, the higher the tempera¬ 
ture of the fire and the lower that of the escaping gases the better 
the economy, for the losses by the chimney gases will bear the same 
proportion to the heat generated by combustion as the temperature 
of those gases bears to the temperature of the fire. Then, if the tem¬ 
perature of the fire is 2,500°, and that of the chimney g*ises 500° above 
that of the atmosphere, the loss by the chimney will be = 20 per 
cent. As the temperature of the escaping gases cannot be brought 
down to that of the boiler, which is fixed, the temperature of the fire 
must be high in order to secure good economy. 


36 GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 


BOILER-FURNACES, GRATE-BARS, AND 
MECHANICAL STOKERS 

The boiler-furnace, its type and special design of firing appliances, 
are matters of no small moment in their contribution to the economy 

of steam-generation. Of the num¬ 
erous models of shaking and tipping 
grates on the market, we can only 
illustrate examples of a few leading 
types. 

The grate-bars in the Tupper 
furnace are in two sections so that 
one-half of the fire can be dressed 
at a time. The bars are placed crosswise and rock on trunnions 
by a hand-lever and connecting-bar. The diagonal spaces in the 
bars are made for any 
size coal required. 

The McClave grate 
is made in fore and 
aft sections, so that 
by separate connec¬ 
tions the front or rear 
section may be shaken 
or tipped for dump¬ 
ing the fire. Each bar 
forms a toothed comb 
with a bell-crank or 
stub-lever and connecting-rod, pivoted to all the bars in the sec¬ 
tion. When the bars are closed the whole grate is a continuous 

surface upon which a slicing-bar may 
be used. 

Fig. 14 shows a shaking and dumping 
grate composed of toothed sectors set 
astride pivoted crossbars with lever ex¬ 
tensions, connected to transverse bars, so 
divided that the grate may be shaken in 
two or three sections. Heavy side-bars 



Fig. 14.—Sector grate-bar. 




Fig. 12.—Tupper model. 














































































































GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 37 


carry the pivoted crossbars. The individual sectors can be readily 
removed when burned out and new ones inserted at trifling expense. 

M ECHANICAL STOKERS 

The Roney mechanical stoker consists of a hopper for receiving 
the coal, a set of rocking, stepped grate-bars, inclined at an angle of 
37° from the horizontal, and a dumping grate at the bottom of the 



incline for receiving and discharging the ash and clinker. The 
dumping grate is divided into several parts for convenience in handling. 

The coal is fed onto the inclined grate from the hopper by a 
reciprocating pusher, which is actuated by an agitator. The grate- 
bars rock through an arc of 30°, assuming alternately the stepped 
and the inclined position. The grate-bars receive their motion from 
a rocker-bar and connecting-rod, and these, with the pusher, are 
actuated by the agitator, which receives its motion through an 
eccentric from a shaft attached to the stoker-front, under the hop¬ 
per. The range of motion of the pusher is regulated by the feed-wheel 
from no stroke to full stroke, and the amount of coal pushed into the 
furnace is adjusted according to the demand for steam. The motion 
of the grate-bars is similarly regulated and controlled by the position 





































































































38 GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 

of the lock-nuts on the connecting-rod. Each grate-bar is composed 
of two parts: A vertical web provided with trunnions at each end, 
which rests in seats in the side-bearers; and a fuel-plate, ribbed on its 


Fig. 16 .—Acme stoker. 



under side, which bolts to the web. These fuel-plates carry the bed 
of burning coal, and, being wearing parts, are made detachable, thus 
reducing the cost of repairs to the minimum. The webs are perforated 
with longitudinal slots, so placed that the condition of the fire can be 

seen at all times without opening the 
doors, and free access had to all 
parts of the grate to assist, when 
necessary, the removal of the clinker. 
These slots also serve an important 
purpose in furnishing an abundant 
supply of air for combustion. 


„ _ « , ,, The Columbian stoker is a special 

Fig. 17.—Soft-coal stoker. , 1 

design for soft coal, which falls from 

the hopper into an upward inclined chute, and is pushed by a 

plunger onto a coking-plate and fixed small grate with an independent 


























































































































































































GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 


39 


air-feed chamber for regulating the coking. The pushing of the 
fresh coal against and under the coking-bank causes the coked coal 
to slide down the inclined grate. A supplementary rocking grate at 
the rear discharges the refuse. The air-feed to the small chamber 
at the top of the grate may be under pressure from a blower, and, 
thus mixing air with the smoke or distillates of the fresh coal, com¬ 
pletes its combustion in the hot part of the furnace. 


The travelling chain-grates are receiving much attention, and we 
illustrate the principles of several designs in this type of grate for 
soft coal. 

In the Playford model a multilink-grate moved by a sprocket- 
shaft carries the coal, fed from a hopper, forward under the boiler; 
the grate returning over a drum at 
the bridge-wall. A screw-conveyer 
brings the ash and clinker forward 
to the pit. 

At the front of the furnace, im¬ 
mediately above the coking end of 
the grate-surface, is a fire-brick arch 
• made of common sized fire-brick. 

The arch becomes highly heated, 
thus making the front end of the 
furnace a reverberatory chamber in which the gases are liberated ■ 
from the coking fuel by distillation. The coked fuel in process of 
combustion is carried by the grate toward the rear of the furnace, while 
the ash and refuse are dumped automatically under the fiat arch at 
the bridge-wall. Forming the top of that which otherwise would 
be an ordinary bridge-wall is a straight arch, overhanging the rear 
end of the grate-surface. 

The Green travelling link-grate, which we illustrate in Fig. 19, is 
made up of long thin links of considerable depth and a large and 
uniform air-space around each link has been provided. The longer 
links afford an increased overhang, so as to shear any clinker which, 
during the travel of the grate, may be brought up to the bridge-wall, 
while at the same time it completely clears the ash from all the air¬ 
spaces of the chain at every turn around the rear sprockets. The 
links of the chain are connected together by bars of oval section, 



1 ' ", J .."A t 


Fig. 18.—Playford stoker. 




































40 GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 


which pass through round holes in the links or clips. The clips are 
engaged by the bars, and they in turn are locked and held in correct 
position by binding links at each end. The holes in the clips have 
a slot extending to the bottom edge, permitting any link or clip to 
be removed and replaced by another one without breaking the chain, 
removing the bars, or interfering with the service. 

The chain is supported at frequent intervals by rolls extending 
under the entire width. 

The framework is well braced and stiffened, to meet the require¬ 
ments of hard service. In stokers exceeding 7J feet in width there is 



provided an additional girder in the centre for the support of the upper 
roll-shafts. 

The driving mechanism consists of an eccentric with a rod and 
lever, communicating motion by a ratchet and pawls to a train of 
gearing. This arrangement permits quick adjustment of speed of 
travel within a wide range. The gearing rests in a strongly braced 
frame. Steel pinions and gears are used throughout. The eccentric- 
connections from the shaft, placed either above or below, are made 
through a long relief-spring, thus preventing undue strain upon the 
gear-train or the chain in case of accident or stoppage. 

A single large grate completely filling the entire furnace width is 
desirable, and more effective than two small grates occupying the 
same space. The flat coking-breast or ignition-arch combined with 
a chain-grate, as previously described, permits the successful use of 



































































GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 41 

grates of any required width, and also obviates the further necessity 
of limiting the size of boiler-units because of inability to provide 
adequate grate-area. 

In the American stoker the coal is carried under the grate from 
the hopper by a spiral screw and forced up over the grate. The 
screw - conveyer or worm 
(shown in the cut) is located 
in a trough that extends un¬ 
der the magazine, beneath 
which is the air-box under 
pressure from a blower. 

In operation the coal is 
fed into the hopper, and is 
carried by the conveyer into the magazine, which it fills, and, over¬ 
flowing on both sides, spreads upon the sides of the grate. The coal 
is fed slowly and continuously, and, approaching the fire in its upward 



Fig. 21.—American stoker under a Worthington water-tube boiler. 



course, it is slowly roasted and coked, and the gases released from it 
are taken up by the fresh air entering through the- tuyeres, which 











































































































































42 GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 


ignites them, and the coal is then delivered as coke on the grate 
above. The continuous feeding gives a breathing motion to this coke- 
bed, thus keeping it open, and free for the circulation of air. 

Every pound of coal fed into the hoppers passes through the gas- 
making process. The non-combustible matter is taken from the 
furnace in the shape of the usual ash. There is practically no soot. 
With these results it is obvious that the combustion must be extraor¬ 
dinarily good, resulting in a practically smokeless stack. 

The finest of slack coal and also lump coal can be used, as any 
lump that can be fed into the hoppers will be crushed by the conveyer, 
there being provided a set of teeth, placed at the mouth of the con¬ 
veyer, against which the coal is squeezed and broken. 

The end-thrust of the conveyer is taken by a frictionless ball¬ 
bearing. 

The conveyer-shaft is a 2f-inch steel shaft, on*which are strung 
what are called “ flights.” These “ flights/ 7 by their reduced diameters, 
distribute the coal equally over the entire width and length of the 
furnace. The entire mass of coke above the tuyere-blocks and over 
the side-grate is ignited. The air enters the stoker from front or 
rear beneath the hopper, and discharges through the tuyere-openings. 
The discharge of air into each stoker is regulated by a wind-gate 

located at the mouth 
of the wind-chamber. 

Air is supplied to 
the ash-pit by supple¬ 
mentary pipes from 
the main air-trunk. 

The Jones stoker 
consists of a plunger 
which may be oper¬ 
ated directly by a 
steam-piston, and which pushes a charge of coal, falling from the 
hopper onto the fore-plate of the grate, where it is coked, the smoke 
and gases being drawn into the hot fire and burned. These stokers 
are well adapted to other than boiler-furnaces and operated by levers 
in place of the steam-cylinders. 




































































GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 43 


L I Q u I I) F IJ E L 


Of all forms of liquid fuel crude petroleum lias become the standard 
lor economy, and its increasing production has so decreased its cost 
for fuel that in many parts of this country and in other countries it is 
cheaper than other fuels. 

The methods of its economical use have been so improved by 
trials and experience derived from the various detailed tests of the 
past few years, that its best results are now realized in very exact 
designs of furnace-construction. 

Some of the advantages in the use of petroleum for steam-making 
are that its heating power is greater per pound than that of any solid 
fuel; that it permits of continuous firing in a closed furnace, free from 
draughts of cold air; that its combustion is complete, with no loss of 
heat by ashes, smoke, or soot; and that the quantity of heat required 
to maintain a constant pressure of steam may be controlled by the 
simple adjustment of a valve in the oil-supply pipe. The boiler-tubes 
are always clean and in the best condition for the transmission of heat 
to the water; starting and discontinuing of the fire are but the work 
of a moment, and all cleaning of ashes and debris avoided. The ad¬ 
mission of air being under complete control, and the fuel being burned 
in atomized particles in contact with the air, only a small excess of air 
above that actually necessary for the complete combustion of the fuel 
being required; all these are points of economy. 

The relative commercial value of coal and petroleum for steaming- 
fuel, apart from their convenience in operating a steam-plant, may be 
summed up in their relative heat-unit values. A net ton of coal is 
credited with 29,000,000 heat-units; a barrel of oil of 42 gallons, 
weighing 6.8 pounds per gallon, at 19,000 heat-units per pound, foots 
up to 5,426,400 heat-units, or 5J barrels to equal 1 ton of coal; so 
that at 90 cents per barrel for oil, it is equal in heat-unit value to coal 
at $4.80 per ton; but where coal is dear and oil as low as 50 cents 
per barrel, it is equal to coal at $2.60 per ton, and in locations where 
coal is about $6 per ton the difference in favor of oil is very apparent. 

The burners or injector-nozles are made in a variety of forms; 
but all operate on the same principle. The steam-and-air method of 
atomizing the oil has not as yet become assured as to the use of 


44 GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 


one or both combined, but so far the practice has favored steam as 
the atomizing agent, with an indraught of air by the force of the jet. 
A combined stealn-ancl-air jet or an air-jet alone requires the use of 
an air-compressor, and if such is installed with independent power 
the steam can be left out of the process with the most economical 
results, for the steam requires a high temperature added before 
dissociation, and only then returns its absorbed heat by the reunion 
of its hydro-oxygen elements. 

There is quite a wide-spread misconception regarding the part 
that the steam which is used for atomizing purposes plays in effecting 
combustion. It is supposed by many that after atomizing the oil 
the steam is decomposed and that the hydrogen and carbon are again 
united, thus producing heat and adding to the heat value of the fuel. 
While it may be true that the presence of steam may change the 
character and sequence of the chemical reaction, and result in the 
production of a higher temperature at some part of the flame, such 
an advantage will be offset by lower temperatures elsewhere between 
the grate and the base of the stack. All steam which enters the fur¬ 
nace will, if combustion is complete, pass up the stack as steam, also 
carrying with it a certain quantity of waste heat. The amount of 
this waste heat will depend upon the amount of steam and its tem¬ 
perature at the entrance of the furnace. The quantity of available 
heat, measured in thermal units, is undoubtedly diminished by the 
introduction of steam. In an efficient boiler it is quantity of heat 
rather than intensity that is wanted. For many manufacturing 
purposes intensity of heat may be of primary importance, but in a 
steam-generator a local intense heat is objectionable on other grounds 
than those of economy, viz., its liability to cause leaky tubes and 
seams from the unequal expansion of heating-surfaces. 

In a series of naval official trials with crude-petroleum fuel, the 
following conclusions were arrived at: 

“ a. That oil can be burned in a very uniform manner. 

“b. That the evaporative efficiency of nearly every kind of oil per 
pound of combustible is probably the same. While the crude oil 
may be rich in hydrocarbons, it also contains sulphur, so that, after 
refining, the distilled oil has probably the same calorific value as the 
crude product. 


GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 45 

“ c • That a marine steam-generator can be forced to even as high 
a degree with oil as with coal. 

u d. That up to the present time no ill effects have been shown 
upon the boiler. 

u e. That the firemen are disposed to fayor oil, and therefore no 
impediment will be met in this respect. 

“ /. That the air requisite for combustion should be heated if pos¬ 
sible before entering the furnace. Such action undoubtedly assists 
the gasification of the oil-product. 

“ g. That the oil should be heated so that it can be atomized more 
readily. 

“ h. That when using steam higher pressures are undoubtedly more 
advantageous than lower pressures for atomizing the oil. 

“ i. That under heavy forced-draught conditions, and particularly 
when steam is used, the board has not yet found it possible to prevent 
smoke from issuing from the stack, although all connected with the 
tests made special efforts to secure complete combustion. Particularly 
for naval purposes is it desirable that the smoke nuisance be eradicated, 
in order that the presence of a warship may not be detected from 
this cause. As there has been a tendency of late years to force the 
boilers of industrial plants, the inability to prevent the smoke nuisance 
under forced-draught conditions may have an important influence upon 
the increased use of liquid fuel. 

“ j. That the consumption of liquid fuel cannot probably be forced 
to as great an extent with steam as the atomizing agent as when com¬ 
pressed air is used for this purpose. This is probably due to the 
fact that the air used for atomizing purposes, after entering.the fur¬ 
nace, supplies oxygen for the combustible, while in the case of steam 
the rarefied vapor simply displaces air that is needed to complete 
combustion. 

“ k. That the efficiency of oil-fuel plants will be greatly dependent 
upon the general character of the installation of auxiliaries and fit¬ 
tings, and therefore the work should only be intrusted to those who 
have given careful study to the matter, and who have had extended 
experience in burning the crude product. The form of the burner 
will play a very small part in increasing the use of crude petroleum. 
The method and character of the installation will count for much, 
but where burners are simple in design and are constructed in ac- 


46 GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 


cordance with scientific principles there will be very little difference 
in their efficiency." 

It may be further said that the heat of steam at high boiler- 
pressure adds greatly to the atomizing effect by heating the oil in its 
passage through the injector and thus vaporizing its more volatile 
constituents; whereas the cooling effect, by the expansion of com¬ 
pressed air, would have an opposite effect, unless the compressed 
air could be highly heated by passing through a coil in the smoke- 
chamber. 


PETROLEUM-OIL BURNERS 


In Fig. 23 we illustrate an oil- and air-burner in which the oil 
enters by the pipe A to the central nozle with its regulating-valve C. 

The compressed air enters through the 
pipe B and issues through an annular 
nozle, and is retained b}^ an outer nozle 
which may be more or less extended for 
a thorough atomization of the oil. 

A burner of English origin is shown 
in Fig. 24, for the combined use of oil, 
steam, and air, which are combined in 
an expanding nozle. The oil enters by 
the rear pipe, and its flow is regulated by a needle-valve. Steam 
enters by the middle pipe, forming an annular jet around the oil. while 



Fig. 23.—Oil- and air-burner. 



Fig. 24.—Oil-, steam-, and air-burner. 


the air enters by the large pipe and forms an annular jet surrounding 
both oil and steam as the combination enters the expanding nozle. 

In Fig. 25 is shown, in plan and section, an oil-burner used on the 
locomotives of the Southern Pacific railroads. 




















































































GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 47 

It is a combined oil-, steam-, and air-burner with a wide, thin mouth 
and chambers closed at the sides, so that the compartments are 


•X; 


m 


m 

o 1 ^ 

1 < 4 

< “! i 

Ji- I s 

ftf 

O < •/ 

uj „ ; 

*-iA 




^ rr 

.OIL. 


• lo 



OIL/1 V'PIPE 


i 1 —-#^5 v v--h !! 

! F--j$z£r-31, 
! ! O i 


1 (_ ' 

r<5Tf 



GO 


END VIEW 


OIL /STEAM INNER TUBE 


— 






_ 

VA AIR < 



Fig. 25.—Flat-nozle burner. 


separated in tiers, one above the other. Oil flows along the flat top 
chamber, with the steam in the central chamber to heat the oil, and 
the oil, steam, and air meet at the 
end of the inner nozle, where the 
oil is atomized in contact with 
the air and steam and projected 
through the end nozle. 

In Fig.‘ 26 is illustrated the 
Urquhart type of burner, in use on 
the Russian railways. It is a com¬ 
bined oil-, steam-, and air-burner. 

Steam enters the hollow valve-spin¬ 
dle through side-ports, while the oil 
enters by a side-pipe and through an annular aperture outside of the 
steam, the nozle of which extends into a hollow stud between the 
plates of the boiler-front. A plate held off from the boiler carries 
the injector with an air-space to give air to the jet in the stay-tube. 

The Oil City burner (Fig. 27) is of the oil and steam combination 
type, with a cap over the end for inducing a draught of air around 
the oil- and steam-jet. The nozle is made long that the steam on the 
outside of the oil-nozle heats the oil for more perfect atomization. 
The oil- and steam-flow are both adjustable by valve-wheels. 

The F. M. Reed burner (Fig. 28) is somewhat novel in the manner 
of combining the oil, steam, and air. 

The oil-flow, regulated by an outside valve, enters through the 






























































































































48 GENERATION OF STEAM—FURNACES AND THEIR ADJUNCTS 


valve-spindle, surrounded by steam from a side entrance, both issuing 
through a short expanding nozle into a chambered nozle, which 



completes the atomizing of the oil; outside of this is a larger chambered 
nozle through which air is drawn by the force of the jet, and, mixing 



with the atomized oil and steam, the final issue to the furnace is ready 
for complete combustion. 




























































































CHAPTER IV 

TYPES OF BOILERS 


One of the earliest types of the modern water-tube boiler was 
made in 1804 by John Stevens at Hoboken, N. J., and with its twin- 
screw propellers is now preserved in the Stevens Institute as the cen¬ 
tury memento of our present water- 
tube boilers and of the principles of 
twin-screw propulsion. After forty 
years the same boiler, engine, and 
screws were placed in a boat of the 
original dimensions and propelled at 
the rate of eight miles per hour. 

Boilers of the shell type continued 
in use as standard form during the 
nineteenth century, with an occa¬ 
sional interpolation of a water-tube boiler, a flash-boiler, and inter- 
circulating coil-boilers, as, for example, the Perkins type, which carried 
steam at 1,000 pounds pressure per square inch and was applied to 
a steam-gun which was exhibited in New York in 1839 and operated 
by the author. 

The most simple form of boiler is the long, plain shell now much 
used on sugar-plantations, and under which bagasse is used for fuel. 


E 



Fig. 29.—Stevens boiler. 



Fig. 30.—Cylinder boiler. 


These boilers are usually set in nests hanging from beams supported 
by the side walls, and are closed in at their half-diameter. Their 
boiler-power may be computed at one-half their shell-area divided by 
10 per horse-power. 


49 


























































































50 


TYPES OF BOILERS 


The double-flue, cylindrical shell-boiler was a favorite form with 
wood-burning furnaces for steam-boats and wood-working mills, 



Fig. 31. —Double-flue boiler. 


and is still in use in modified forms. One-half the shell- and all the 
flue-surface, divided by 11, equal the boiler horse-power. 

The internally fired flue-boiler is now becoming antiquated from 
its limited furnace capacity, and has finally merged into the cor¬ 
rugated tubular furnaces of the marine type. 

The horizontal tubular boiler has been a standard type for three- 
quarters of a century, and is yet the leading steam-maker within the 
range of its allotted pressure. For ease of care and convenience of 

repair it stands at the head 
of the list in number in use 
in all countries. When well 
proportioned for its work 
its economy is unchallenged, 
and at pressures of 100 
pounds, and under, it is, 
when well constructed and 
cared for, as safe from rupture as other types. 

One-half the shell- and all the outside tube-surface, divided by 
14, equal the boiler horse-power. 

The Galloway boiler, an English type, has a cylindrical shell with 
an oval flue and is internally fired. It has two furnaces which merge 
into a combustion-chamber at the rear. This chamber is fitted with 






- T'l 






lfli§P 

LL- —l i i "L 



Fig. 32. —Cylindrical tubular boiler. 


Fig. 33.—Galloway boiler. 










































































































































TYPES OF BOILERS 


51 


tapered water-tubes for the purpose of increasing the effective heat¬ 
ing-surface of the boiler and of promoting a better circulation of water; 
they also act as stays, largely increasing the strength of the flue to 
which they are fitted. 

The heated gases after passing through the internal combustion- 
chamber return along the outside of the shell to the front and again 
to the rear end and to the chimney. It is considered an efficient 




Fig. 34.—Plan and section of boiler-setting. 


boiler. All the internal surface of flue and tubes and the shell exposed 
to heat, divided by 12, equal the boiler horse-power. 

The setting and care of a cylindrical tubular boiler are matters 
of careful consideration. Air-leaks in the brickwork adulterate the 
hot gases of combustion and are the cause of fuel loss; so that too 
much pains cannot be taken in making the joints as close as the bricks 
will allow and fully flushing every joint with mortar. 

Fig. 34 shows the plan and elevation of a flush-front boiler-setting 
with a filled-in rear chamber and recesses for catching the light ashes 
that pass over the bridge-wall. The air-space in the walls is shown 
in the cut much wider than needed, as 2 inches is wide enough for 
the largest boilers. 


























































































































































































52 


TYPES OF BOILERS 


The filling of the rear chamber is of doubtful value, as the large 
area of this chamber serves as a setting-place for the light ashes that 



Fig. 35.—Section with flush front, open chamber. 


are carried over the bridge-wall, and the large volume of hot gases 
and ashes is a strong radiant of heat to the rear end of the boiler. 

In Fig. 35 is a section with solid brick walls carried above the top 
of the boiler and with an extension of the grate-surface, onto the 
bridge-wall and a support of the back-chamber closure by a T beam. 


iirrniiiiriIHF^' 

i 1 1 1 1 1 1 1 1 1 1 1 1 1 

11 1 1 i i i l 1 1 ! 1 1' l 

1111 1 1 1 1 1 1 1 1 '1 IT 


u 




, . 

1 


. - r . 

i i 

1 


i 

1 

1 

i i 

1 




I 


i i 


T 

~T~ 

, i , 


r 


i i 


i 


i 


i 


i i 

i 

1 





T J U 

. L 

J 

i_i 

1 i 1 1 1 1 1 1 1 II 

1 1 1 1 11 1 1 1 1 1 1 1 1 1 1 

r i i i r t i i i i i 

wti i t t v w r t i r i i 



Domes on this type of boiler are not recommended, because they 
are a source of weakness; but they have their advocates on the plea 










































































































































































































TYPES OF BOILERS 


53 


that they are steam-reservoirs ami promoters of dry steam. A trifle 
larger shell and a dry pipe at the same cost is the safe and preferable 

plan. 

Fig. 36 shows the plan and section of the setting of a boiler with 
an overhang front smoke-chamber, which rests on a half-front frame. 


THE ROBB-MUMFORD BOILER 


SMOKE OUTUr 


This internal-fired cylindrical boiler is a recent type of construc¬ 
tion, with an internal fire-box of the Morrison corrugated type 
and with its full area of head filled with tubes; the lower shell is 
inclined, as is also the steam¬ 
drum above, in order to facilitate 
water-circulation. The design is 
very compact and enclosed in 
a brick-lined metal casing. It 
appears to be a good steamer. 

The fire-surface of the tubes, 





fire-box, and all of the shell ex- ' ' . 

, , . . t • i i i ir. Fig. 37.—Internal fired, cylindrical tub- 

posed to heat, divided by 12, u lar boiler, 

equal the boiler horse-power. 

The “Continental type” of marine boiler has a double corrugated 
tubular furnace with cylindrical shell and return-tubes. This form 
of construction is the general one for marine use, and is made in the 



large units with multiple furnaces. It is a modification of the “Scotch 
boiler” and is also made with double ends, set back to back with 
common or separate combustion-chambers. 












































































54 


TYPES OF BOILERS 


The down-draught system of combustion as applied to a Hein boiler 
is shown in Fig. 39, in which is illustrated the Hawley furnace; c is a 

tubular grate; d, tube-connec¬ 



tion between the grate-header 
and front drum; b, tube-con¬ 
nection between the grate- 
header and rear drum, with 
blow-off. 

The Hein boiler has its 
water-legs in form of a 
wrought-iron chamber flanged 
and riveted to the steam- 
and water-drums, which are 


stayed throughout their breadth. The tubes are expanded in the 
heads, with a hand-hole plate opposite each tube for cleaning and 
repairs. Their steaming capacity is 
about 11 feet of heating-surface per 
boiler horse-power. 

Among the many pipe-boilers 
on the market for special purposes 
and claims for efficiency and high- 
pressure safety, we illustrate the 
Herreshoff boiler (Fig.40), which has 
gained much credit in the steam- 
yacht service. ' The inner coil is the 
evaporator and receives the feed¬ 



Fig. 40.—Herreshoff boiler. 


water through the heater-coil in the smoke-chamber. The conical 

coil at the top also acts as a heating-cham¬ 
ber and feeds the inner coil, while the 
outside coil is the superheater. 

A separator-drum at the side entraps 
any superfluous water that may be fed to 
the boiler, and also acts as a separator, 
giving to the superheater dry steam. 

The Thornycroft boiler (Fig. 41) is shown 
as a type in principle of a number of water- 



Fig. 41.—Thornycroft boiler. 


tube boilers on the market in Europe and the United States. It 
consists of a large steam-drum above and a water-drum below, con- 

















































































































































TYPES OF BOILERS 


55 




nectecl with a large number of bent tubes. The water-return is 
through a large tube at the rear end of the boiler. The same princi¬ 
ple of action, with different de¬ 
signs in construction, is carried 
out in the Yarrow, the Moyes, 
and the See water-tube boilers, 
with straight tubes; the Boyer 
water-tube boiler, with return 
bend coils, and the Meehan and 
Sterling water-tube boilers, with 
bent tubes. The Du Temple ma¬ 
rine water-tube boiler (Fig. 42), 
made in France, is of the Thorny- 
croft type and is here illustrated. 

Although patented in 1876 it 
has all the essential qualities of 
the later water-tube boilers. A 
quick and powerful steamer, it 
has been much in use in the 




<7 



ler - ... 

,(A/ 

vjji 


-- 



j; 

l* 


/ 

i 

ii 



Fig. 42.—Du Temple boiler. 



tube boiler. 


torpedo-boat service. Ample circulation is 
provided for by the direct back connections 
between the steam- and water-drums. The 
cut shows a half-section of each side. 

We do not deem it expedient as the 
object of this work to illustrate the large 
number of boilers on the market, whose 
builders claim merit and public favor far 
their special designs; nor can we go into 
the merits of their tests of economy and 
usefulness with any degree of safe judg¬ 
ment; rather let their work with users tell 
the story of their worth. 

Among the vertical water-tube boilers 
with straight tubes between the steam- 
and water-drums with outside furnaces we 
illustrate the Wood boiler (Fig. 43), which 
has large steam- and water-drums with 




























































































































































5G 


TYPES OF BOILERS 


stayed heads; the tubes are arranged in front and back sections with a 
brick or tile partition carried up from the lower head to near the 
top, so that the products of combustion traverse the whole length 
of the tubes up and down and out to the chimney at the rear. 

The arched furnace projects at the front, 
and the whole boiler is enclosed in brick 
walls. Circulation is obtained by the more 
active upward current, with its steam in the 
fire section and induced down-flow in the 
rear section. 

Another design is the Cahall water-tube 
boiler (Fig. 44) with straight, nearly vertical 
tubes between an annular steam-drum at the 
top, through which the smoke passes, and a 
water-drum at the bottom. The furnace 
and combustion-chamber project outside at 
the front, and a circulating-pipe is carried 
from the steam-drum to the water-drum 
outside of the brick setting. 

In Fig. 45 is shown the duplex water-tube boiler made by the 
Philadelphia Engineering Works. This boiler has straight vertical 
tubes between a pair of steam- and water-drums. The steam-drums 
are connected with several cross-pipes, as 
shown in the cut, and the water-drums are 
connected by a single neck. A brick wall 
between the two stacks of tubes directs the 
products of combustion upward through the 
tube-stack next to the furnace and down 
the opposite stack and to the chimney. 

The water-circulation takes the same course 
through the tube-stacks and drum-connec¬ 
tions. 

In Fig. 46 is a section of the Sterling Fig. 45.—Duplex boiler, 
water-tube boiler, which consists of three 

upper or steam-drums and one lower or mud-drum, with the tube- 
ends bent so that all of them can properly enter the drums. 

The steam-spaces of all the upper drums are connected, while the 
water-spaces of only the front and rear drums communicate. The 






Fig. 44.—Cahall boiler. 












































































































TYPES OF BOILERS 


57 


drums are made of flange steel, while the tubes are lapwelded steel, 
tested at 1,500 pounds pressure per square inch. These drums and 
the tubes form the boiler proper. 

It is designed to be a safety-boiler, and the absence of flat sur¬ 
faces renders stay-bolts and braces unnecessary; it will be seen that a 



Fig. 46.—Sterling water-tube boiler. 


fire-brick arch is built over the grates and immediately in front of the 
first section of tubes. This arch absorbs heat from the fire on the 
grates and becomes an incandescent, radiating surface. Tile pai ti- 
tions are so arranged that the hot gases pass the entire length of the 
three stacks of tubes. 

The feed-water enters the rear upper drum, the coolest part of the 
boiler, and as it descends to the mud-drum is gradually heated by the 
gases, passing to the chimney to a sufficient extent to render insoluble 
much of the sediment that it contains, which is deposited in the mud- 
drum in the form of mud or sludge, from which it may be blown 





























































































58 


TYPES OF BOILERS 


off. The mud-drum is protected from the intense heat of the furnace 
by an ample bridge-wall, and acts as a settling-chamber. 

The middle drum is connected to a supplementary drum by a 
series of tubes in the same manner as the others, and receives the 

priming, which, falling through the 
tubes to the lower drum, is recon¬ 
verted into steam and superheated. 

By suitably disposed fire-tile 
partitions or baffle-walls, the gases 
from the furnace are led first up 
among the first bank of tubes, de¬ 
pending from the front drum, thence 
down the middle bank, thence up 
the rear bank, and on into the 
chimney at a reduced temperature. 

In this long and circuitous pass¬ 
age the gases come in contact with 
all the tubes, which method insures 
a more or less complete delivery of their heat to the water. 

In Fig. 48 is illustrated the latest style of the Babcock & Wilcox 
water-tube boilers, the most compact and economical design of all 
of their extensive manufacture, and best suited for generating high- 
pressure steam. 

The vertical header style has the same general features of construc¬ 
tion as their other styles, with the exception of having the tube-sheet 
side of the header “stepped” so that the header may be placed at 
right angles to the drum, instead of having it inclined, as in previous 
designs. This form permits of a shorter brick setting, thereby re¬ 
ducing the cost of erection and the floor-space occupied. 

The last step in the development of the water-tube boiler, beyond 
which it seems almost impossible for science and skill to go, consists in 
making all parts of the boiler of wrought steel, including the sinuous 
headers, the cross-boxes, and the nozles on the drum. This was 
demanded to answer the laws of some of the Continental nations, and 
the Babcock & Wilcox Co. have at the present time a plant turning 
out forgings, as a regular business, which have been pronounced to be 
“a perfect triumph of the forgers’ art.” 

One of the important points in the generation of steam is that> it 



Fig. 47.—Sterling water-tube boiler. 
































































TYPES OF BOILERS 


59 


should be dry as it leaves the boiler; and in this class of boilers the 
large disengaging surface of the water in the drum, together with the 
fact that the steam is delivered at one end and taken out at the other, 
secures a thorough separation of the steam from the water, even 
when the boiler is forced to its utmost. Most tubular, locomotive, 
and sectional boilers make wet steam, “priming” or “foaming" as it 
is called, and in many “superheating surface” is provided to “dry 



_ 




T i f i 




,r |V 111.,,!. '] I; l„! t, 


B— 

. 1 .,, 1 .i 1 . .i.. i .T .. ii i IT ,i 


l t 1 


- y 








.;, t 


Fig. 48.—Babcock &'Wilcox vertical header-boiler. 


the steam”; but such surface is always a source of trouble, and is 
incapable of being graduated to the varying requirements of the 
steam. No part of a boiler not exposed to water on the one side 
should be subjected to the heat of the fire upon the other, as the un¬ 
avoidable unequal expansion necessarily weakens the metal and is a 
serious source of danger. Hence a boiler which makes dry steam is 
to be preferred to one that dries steam which has been made wet. 

The vertical cylindrical tubular boiler is a convenient type for 
cramped fire-room space and for portable use. It is most suitable for 



























































































































































































































GO TYPES OF BOILERS 

small units of power, but is not considered to be of economical form. 
We illustrate three models which cover their essential differences. 

First, an English design with submerged 
tubes and enlarged water- and steam-spaces, and 
in which a diaphragm is inserted among the 
tubes to divert the circulation across the tubes 
and clear the tube-head from accumulation of 
steam. 

Secondly, a submerged-tube vertical boiler 
as ordinarily constructed, in which all the tube- 
surface and the surface of the furnace divided 
by 10 equal the boiler horse-power. 

Thirdly, the one more commonly in use, the 
through-tube model, in which the upper ends 
of the tubes are exposed to undue temperature 
and to the troubles arising from overheating the upper ends and tube- 
head, which condition weakens the expanded joints, causing leakage. 
This, together with the difficulty of cleaning the tubes on the inside 
and of removing the scale from the outside, or clearing the fire-tube 



Fig. 49.—Vertical sub¬ 
merged-head boiler. 



Fig. 50.—Submerged-tube vertical boiler. 


Fig. 51. — Vertical-tube boiler. 












































































































































































































































































TYPES OF BOILERS 


61 


sheet from scale and mud that fall upon it, is a serious drawback 
in the use of this type of boiler, except for temporary or portable 
necessity. 

The water-surface of such boilers is small for the quiet delivery of 
steam; foaming is waste, and they should not be forced beyond two- 
thirds of their rated power. 

THE HORSE-POWER RATING OF BOILERS 

The work of a boiler to convert water into steam requires some 
unit to represent its general efficiency as a steam-producer. The 
method of Watt, now abandoned, was the evaporation of 1 cubic 
foot of water per hour to equal a boiler horse-power. The method 
of to-day is one that figures on evaporating 30 pounds of water per 
hour from 100° F. and at 70 pounds gauge-pressure as equivalent to 1 
boiler horse-power. This standard is also equivalent to the evapo¬ 
ration of 34.5 pounds of water per hour from and at 212° F. As a 
boiler can in no way develop power of itself, it would seem that to 
assign to it the term “horse-power” is illogical, because economy in 
the use of steam must depend upon the engine alone, and economy 
varies greatly with the various types of engines. 

The term “horse-power” as applied to a boiler seems justified, 
however, as a matter of convenience, and probably conveys as in¬ 
telligent an idea as to the power the boiler is able to furnish as any 
other term. 

The power of a boiler to make steam depends upon the amount 
of heat generated in the furnace, and on the proportion of that heat 
which is transmitted to the water in the boiler. 

The amount of heat liberated through combustion depends upon 
the quality of the fuel, the rate of combustion, and the size of the grate. 

The rate of combustion varies with the draught, quality of coal, and 
the skill with which the fire is handled. As a general rule a moderate 
rate of combustion is preferable, as the combustion is more likely to 
be complete and the heating-surfaces are thus permitted to take up 
a larger portion of the heat produced, while if the combustion is too 
rapid a large amount of heat escapes to the stack. On the other 
hand, when the combustion is too slow a considerable excess of air 
is admitted to the furnace through the grates and the loss of heat by 
radiation and conduction is proportionately increased. 


62 


TYPES OF BOILERS 


The heating-surface of a boiler is a factor which also requires 
consideration. The heating-surfaces of the various kinds of boilers 
differ in their efficiency; thus, for instance, the tubes of a return 
tubular boiler are not equal in radiating value to the shell for equal 
areas. Neither can both ends of a tube be of equal value, as the 
value decreases with the length of the tube. It is therefore of little 
advantage to have the length of the tube more than fifty times its 
diameter. 

The rating of a boiler as now sold is figured from the amount 
of its heating-surface, allowing from 11 to 12 square feet per horse¬ 
power. It is evident that this method of rating is an invitation to 
boiler-makers to increase the heating-surface at the expense of the 
boiler capacity. 

This has no bearing upon the power that can be obtained from a 
horse-power of the boiler. The type and model of the engine in its 
economy of steam used in pounds per horse-power are the real factors 
that give the value in power that can be obtained from a boiler 
horse-power; so that a boiler horse-power divided by a steam-engine 
horse-power in pounds of steam, equals the steam-engine horse-power 
available per boiler horse-power. 

HEATING- AND GRATE-SURFACE. FOR BOILERS 

The amount of heating-surface per horse-power varies very much 
in the different types of boilers and with the amount of fuel burned 
per square foot of grate. The square feet of heating-surface and 


Table VI.—Approximate Proportion of Heating-Surface and Grate-Surface 
per Horse-Power, etc., of Various Types of Boilers. 


Type of Boiler. 

Square feet 
of heating- 
surface per 
horse-power. 

Coal 

per 

square 
foot of 
heat- 
ing- 
sur- 
face. 

Rela¬ 

tive 

econ¬ 

omy. 

Rela¬ 
tive 
rapid¬ 
ity of 
steam¬ 
ing. 

Heating- 
surface per 
square foot 
of grate. 

Pounds of 
coal per 
square foot 
of grate. 

Pounds of 
water per 
pound 
of coal. 

Water-tube. 

10 to 12 

.3 

1 .00 

1.00 

35 to 50 

12 to 20 

9 to 12 

Cylind’l tubular. 

14 “ 16 

.25 

.91 

.60 

25 “ 35 

10 “ 15 

8 “ 11 

Vertical tube.... 

15 “ 20 

.25 

.80 

.60 

25 “ 30 

10 “ 15 

8 “ 10 

Locomotive. 

12 “ 16 

.275 

.85 

.55 

50 “ 100 

20 “ 40 

8 “ 11 

Flue. 

8 “ 12 

.4 

.79 

.25 

20 “ 25 

10 “ 20 

8 “ 10 

Plain cylindrical. 

6 “ 10 

.5 

.69 

.20 

15 “ 20 

15 “ 25 

7 “ 9 


























TYPES OF BOILERS 


63 


grate-surface are so variable in the various types and many designs 
of the same type, that no condition as to actual performance or effi¬ 
ciency of any boiler can be made except as deduced from the actual 
work of one of its own type and model under equal conditions of 
operation. 

In the foregoing table are values nearly covering the limits of 
practical work with various types of boilers. 


THE INDICATORS OF BOILER-CONTROL 


The safety-valve, the pressure-gauge, and the water-gauge are the 
safety-indicators of all steam-generators and as such are to be watched 
with all the care of the engineer as indicating what is the condition 
between the furnace and the engine. 

The size of the safety-valve is an important matter, and it is well 
to consider the area of the grate, the weight of fuel burned, and 
the steam-pressure when calculating the required area of a safety- 
valve, because, other things being equal, the volume of steam gen¬ 
erated in a given time will depend upon the weight of the coal burned, 
and the velocity of escape will depend upon the pressure. 

A general rule or formula given by Professor Thurston is: Area = 


0.5w 


^ ^ , in which w = weight of steam made per hour in pounds, and p 

the gauge-pressure. Another formula, of unknown source, is based 

, , . A , , 22.5G 

upon the grate-surface and gauge-pressure: Area ot valve = p + g ^ 


in which G = grate-surface in square feet; p = gauge-pressure. 

When the area of the grate and the steam-pressure are not con¬ 
sidered, 1 square inch of valve-area should be provided for each 
3 square feet of grate-surface for spring-loaded or “pop” valves, 
and 1 square inch of valve-area for each 2 square feet of grate- 
surface for the lever-and-weight variety. A safety-valve should be 
proportioned for the lowest regular pressure to be carried because 
steam of higher pressure possesses a smaller volume and escapes at a 
much higher velocity, so that a smaller valve will discharge the same 
weight of steam in less time; therefore, as the pressure becomes higher 
the valve may be made smaller. 




64 


TYPES OF BOILERS 


In the following table are given the safety-valve areas in square 
inches per square foot of grate and various pressures based on the 
velocity and weight of issuing steam at the different pressures. 


Table VII.— Areas of Lever Safety-Valves for Each Square Foot of 

Grate-Surface. 


Gauge- 

pressure. 

Area in 
square 
inches.' 

Gauge- 

pressure. 

Area in 
square 
inches. 

15 

1.250 

65 

.468 

20 

1.071 

70 

.441 

25 

.937 

75 

.416 

30 

.833 

80 

.394 

35 

.750 

85 

.375 

40 

.681 

90 

.357 

45 

.625 

95 

.340 

50 

.576 

100 

.326 

55 

.535 

105 

.312 

60 

.500 

110 

.300 


Gauge- 

pressure. 

Area in 
square 
inches. 

Gauge- 

pressure. 

Area in 
square 
inches. 

115 

.288 

165 

.208 

120 

.277 

170 

.202 

125 

.267 

175 

.197 

130 

.258 

180 

.192 

135 

.250 

185 

.187 

140 

.241 

190 

.182 

145 

.234 

195 

.178 

150 

.227 

200 

.174 

155 

.220 

225 

.166 

160 

.214 

250 

.158 


In Fig. 52 is shown the lever safety-valve, the lever of which is 
of the third order. 0 is the fulcrum; A the distance from the fulcrum 

to the centre of the valve; B the dis¬ 
tance from the fulcrum to the centre 
of gravity of the lever; C the distance 
from the fulcrum to the centre of the 
weight; D total length of the lever, 
and S the diameter of the valve-open¬ 
ing, all in inches. G = the weight of 
the lever at its centre of gravity, and W the weight of ball; V = the 
weight of the valve and spindle; P = pressure in pounds per square 
inch. 

W_ ^ 2 X •7854> < P X A — (GxB) — (V xA) 

C 

^ S 2 X .7854xPxA —(GxB)-(VxA) 

L- w “ 

In Fig. 53 is shown a differential safety-valve in which the enlarged 
area of the upper valve compensates for the differential tension of 
the spring upon opening the valve, thus causing the valve to open 
wide without increase of boiler-pressure. 

Another form of spring safety-valve, known as the “pop” or reac¬ 
tionary valve, of which the Ashcroft is a good example, is one in 


i*---c 

t 


-B 



Fig. 52.—Lever safety-valve. # 



















































TYPES OF BOILERS 


65 


which the steam issuing from under the valve is deflected by a curved 
lip or flange in such a manner as to cause an additional pressure by 
its reaction that aids effectively in raising the valve. The pressure 
at which a pop } valve will blow cannot, as a rule, be as closely 



Fig. 53.—Differential safety-valve. 


Fig. 54.—“Pop” safety-valve. 


estimated as with the lever-and-weight style, and must therefore be 
finally adjusted by trial. Fig. 54 shows a section of the consolidated 
pop safety-valve with wing-guides. The seat is narrow and at an 
angle of 45°, above which are the enlarged 
lipped area and shield. 

Water-gauges and their position, with the 
facilities for keeping them in perfect condition, 
are essential to the welfare of a steam-plant. 

Their length should correspond with and cover 
the range of water-level assigned for the different 
sizes and types of boilers. In all cases they 
should be fixed to water-columns or stand-pipes 
containing the gauge-cocks; although with the 
ordinary vertical boilers this is not always a 
fast rule. Their pipe-connections should be so 
arranged that dry steam enters the top of the 
water-column and water enters the bottom from 

a quiet part of the boiler-water, with blow-off Fig 55 _Qui c k- c los 

valves for both water-column and water-gauge. ing water-gauge. 























































































































66 


TYPES OF BOILERS 


A water-column should be blown out at least once a clay, and 
as often as three or four times a day, depending upon the quality of 

the feed-water employed. The gauge- 
cocks should be opened after blowing 
out the column or the glass to see that 
the water-level in the glass tallies with 
the level indicated by the gauge-cocks. 


Pressure-gauges should as a rule be 
placed convenient for observation, with 
the shortest piping possible, and with a 
siphon beneath the gauge for its protec¬ 
tion from injury from steam within its 
spring. A cock on the gauge is neces- 



Fig. 56.—Bourdon gauge. 


sary, and if the pipe is of a length to accumulate water, a pet-cock at 
its lowest point near the gauge serves to blow' out any sediment and 
prove the proper connection of the gauge with the boiler. 

One of the most satisfactory and convenient instruments for the 
engine-room or office, to show the range of boiler-pressure during the 

daily run, is an Edson recording 
steam-gauge, which we illustrate 
in Fig. 57 and detail in Fig. 58. 
The diaphragm D is so corru¬ 




gated that its movement under pressure shall be practically uniform for 
equal increases of pressure. From this diaphragm a connecting-rod, G, 






























































































































































































TYPES OF BOILERS 


G7 


actuates a small crank, H, the shaft of which bears an open segment, 
which actuates a pinion on the arbor of an index showing the pressure 
on the diaphragm. At the same time, by means of levers H 2 , H 3 , 
vertical movement is communicated to a pencil-point, which records 
gradually on a graduated paper ribbon the pressure shown by the 
index as being on the diaphragm. The paper strip has given to it by 
clock-work a regular motion from the drum Iv to Iv 2 , and has marked 
on it vertical spaces corresponding to hours. By this means, not only 
the index-hand shows the pressure put on the gauge, but the pencil 
makes a continuous record showing all fluctuations and when they 
occurred. There is also an electrical-alarm attachment by means of 
which, when the pressure passes a certain 
limit, a bell is rung. 

Fusible plugs are in use and are required 
by law to be applied to boilers of sea-going 
vessels. They are generally composed of 
pure Banca tin, which melts at 443° F., in¬ 
cased in a brass shield and screwed into the 
boiler-sheet from the water side and at the 
highest point subject to exposure to the 
furnace-heat by low water. In Fig. 59 is 
shown an inside and an outside fusible 
plug of the model required by the United States Inspection Service. 
No composition metal is allowed; the diameter of the water-end of 
the tin plug is about one-half inch. 

The feed-pipe should enter a boiler at a convenient point and be 
so arranged on the inside as to prevent as much as possible the 
immediate contact of the feed-water with the highly heated furnace- 
plates or hot part of the tubes. There are many designs of the 
arrangement of feed- and blow-off pipes, adapted to the different 
types and models of boilers in use, so that no fast rule can be 
quoted. 

STRENGTH OF CYLINDRICAL SHELL-BOILERS 

As there are apprehensions among some engineers in regard to 
the direction of the strains in the shell of a cylindrical boiler, we illus¬ 
trate in Fig. 60 these conditions, which are shown by the directions 



Fig. 59.—Safety-plugs. 





























































68 


TYPES OF BOILERS 


of the arrows in the upper and lower half of the shell. It will be seen 
that the actual direction of the pressure is radial; but the resultants 
of the directions of the arrows are only fully effective at the points of 

their angles of position and only as the 
sine of the angle for any single collective 
point in the circumference, and for the 
diameter, as in the diagram; the results 
due to the sines of the radial stresses in 
the upper half are shown in the direction 
of the arrows in the lower half of the 
diagram. The pressure in pounds per 
square inch, multiplied by the semidi¬ 
ameter of the shell in inches, equals the 
strain in a section of the shell 1 inch 
wide. 

The resistance in the shell is the 



Fig. 60.—Strains in a boiler-shell. 


tensile strength per square inch, multiplied by the thickness in deci¬ 
mals of an inch for the sheet alone and an allowance made for the 
loss in strength by the riveted seam. 

For single-riveted seams an allowance of from 40 to 45 per cent, 
of the tensile strength of the sheet should be made and for double- 



9 


Fig. 61.—Double-lap joint. 




riveted seams an allowance of 33 per cent.; making their tensile strength 
55 and 67 per cent, of that of the plate. The strength of the single- 
riveted girt-seam is much greater for any size shell than a single- or 
double-riveted longitudinal seam; besides, the head-support from the 
tubes is fully equal to the strain within their area. The strength of 

































































TYPES OF BOILERS 


09 


the longitudinal seam in all forms of boiler-shells, steam-drums, riveted 
pipes and tanks, determines to a marked degree the pressure which 
the structure is capable of carrying continuously and with safety. 
Boilers are now so generally made of steel plates and rivets that 
we give some details of the make-up of these seams. In Fig. 61 is 




shown the lay-out of a double-riveted lap-joint with the rows staggered, 
which is the strongest joint with two rows of rivets; and in Fig. 62 the 
lay-out of a triple-riveted seam, with an accompanying table of 
thicknesses of plates, sizes of rivets and holes, and their distance 
apart; also the percentage of the strength of the seam in proportion 
to the strength of the plate. 


Table VIII. —Proportions for Boiler-Joints ; Double-Riveted. 



Diameter. 

Centre of 
hole to 
edge 
of plate. 

Pitch op Rivets. 

Lap op 
Plates. 

Percentage of Joint. 

Thickness 

of 

Rivet. 

Hole. 

Centre to centre 
zigzag riveting. 

Zigzag 

Steel plate. 

plate. 

Hori¬ 

zontal. 

Vertical. 

riveting. 

Iron 

rivets. 

Steel 

rivets. 


A 

A 

B 

C 

E 

F 

i 

4 

it 

3 . 

8 

tV 

i 

9 

T 

8 

H 

3 . 

4 

1 

it 

t 

it 

L 

8 

it 

1 

iiV 

it 

it 

3 . 

4 

it 

£ 

it 

1 

1-iV 

lit 

1 

H 

1ft 

lit 

If 

lit 

Bt 

If 

2t 

2f 

2* 

2£ 

m 

3 

3t 

3f 

H 

lit 

If 

lit 

Bf 

It 

1i 2 6 

Itt 

lit 

2£ 

2f 

2f 

2£ 

m 

3 

3t 

3t 

72.48 

67.01 

62.54 

59.44 

58.44 
57.87 
56.46 
54.29 
54.42 

72.48 

71.46 

70.42 

69.55 

68.07 

66.65 

66.00 

66.05 

64.82 












































































70 


TYPES OF BOILERS 


i 

1*6 

3. 

8 

A 

I 

A 

5 . 

8 

It 

n 

4 


Proportions for Boiler-Joints ; Trtple-1 


l L" 1 V 1 V rill 


ft 

8 

n 

1 1 
rs 

3. 

4 

l 

H 

3* 

3fr 

li 

i-A 

5 

PI3 

'>» 

79.14 

72.74 

3 

4 

13 
l 6 

1 

13 

it 

7 . 

8 

It 

ll 3 6 

1A 

lf 

3 f 

3» 

4 

1* 

1 8 

Ht 

lit 

n;ft 

6 

6f 

68.79 

66.18 

64.39 

It 

1 

il 

41 

H 

6f 

63.15 

1 

1-iV 

i-A 

41 

2 

n 

62.27 

1 A 

H 

lit 

if 

4f 

2A 


61.64 

n 

ift 

41 

21 

n 

61.22 


80.34 

79.25 

78.37 

77.46 

76.56 

75.78 

75.04 

74.27 

73.63 


The hydraulic test of a boiler should be at a pressure not more 
than one and a half times the working pressure. 


Table IX. —Safe Working Pressure for Well-Made Cylindrical Tubular 
Boilers with Steel Shells; Double- and Triple-Riveted. 


Diam- 

Thick- 

Steel 

shell. 

Steel 

shell. 

Diam- 

Thick- 

Steel 

shell. 

Steel 

shell. 

eter. 

ness. 

Iron rivets. 

Steel rivets. 

eter. 

ness. 

Iron rivets. 

Steel 

rivets. 

36 

1 

4 

Ill 

121 

Ill 

123 

56 

5 

16 

82 

89 

88 

97 


ft 

TF 

128 

139 

137 

151 


3. 

8 

92 

101 

104 

116 

38 

1 

4 

105 

115 

105 

116 

58 

ft 

nr 

79 

86 

85 

94 


A 

121 

132 

129 

144 


3 

8 

89 

98 

100 

112 

40 

1 

4 

100 

109 

100 

110 

60 

A 

77 

83 

82 

91 


JU 

1 tf 

115 

125 

123 

136 


3 

8 

85 

95 

97 

108 

42 

1 

4 

95 

104 

95 

105 

62 

3 

8 

83 

92 

94 

104 


A 

110 

119 

117 

130 


A 

92 

103 

108 

120 

44 

1 

91 

99 

91 

100 

64 

3 

8 

81 

89 

91 

101 


1 6 

105 

114 

112 

124 


_1_ 

1 6 

89 

100 

105 

117 

46 

1 

87 

95 

87 

96 

66 

3 

8 

78 

86 

88 

98 


A 

100 

109 

107 

119 


-1- 
1 6 

87 

97 

102 

113 

48 

A 

96 

104 

102 

114 

68 

3 

8 

76 

84 

86 

95 


3 

8 

107 

118 

121 

135 


-1- 
1 6 

80 

94 

99 

110 

50 

A 

92 

100 

98 

109 

70 

3 

8 

74 

81 

83 

92 


3 

8 

103 

113 

116 

129 


A 

82 

91 

96 

107 

52 

.3. 

1 6 

89 

96 

95 

105 

72 

3 

8 

72 

79 

81 

90 


3 

8 

99 

109 

112 

124 


1 6 

79 

89 

93 

104 

54 

_3_ 

1 6 

85 

93 

91 

101 


JL 

•l 

89 

98 

104 

117 


3 

8 

96 

105 

108 

120 








Perhaps the most important detail in boiler-construction is the 
bracing of flat surfaces. The end-surfaces of steam-boilers are stayed 
by means of braces extending from the heads to the shell or by longi¬ 
tudinal stays extending from head to head. In all flue-boilers in 
which the flues are riveted to the heads, the flues themselves act as 
stays, and usually have strength enough to dispense with other stays 
below the water-line, except in very large boilers or those adapted 
to very high pressures. The holding-power of wrought-iron tubes 
expanded in the heads is sufficient to withstand any working pressure 











































TYPES OF BOILERS 


occurring in that portion ot the boiler in which the tubes are lo¬ 
cated. This refers especially to stationary boilers. 

Flanging the edges of a boiler-head increases its stiffness along 
the outer edge, and for this reason 2 inches of this outer flanged 



Fig. 63.—Stayed boiler-head. 


surface may be left to take care of itself. The influence of the 
flange extends inward, and no braces need be located within 4 inches 
of the flange radius for pressures less than 150 pounds per square 

inch. 

The holding-power of the tubes imparts sufficient stiffness to the 
boiler-head not to require braces nearer than 4 inches, so that in all 
ordinary calculations the area to be supported would be represented 



by the segment of a circle (as shown in Fig. 63) of 6 inches less radius 
than the boiler-head and its base-line or chord 4 inches above the 
tubes. 

The location of the stay-centres is not easily worked out except 
on the drawing-board, but the area to be stayed in any given case can 
































72 


TYPES OF BOILERS 


be obtained by computation of the area within the lines as above de¬ 
scribed. For example, for a boiler-head 58 inches in diameter with 
a required braced area of 353.77 square inches, the load to be carried 
by the braces will be equal to the area found multiplied by the maxi¬ 
mum safe working pressure in pounds. If the pressure is to be, say, 
130 pounds per square inch, then the total load will be 353.77 X130 = 
45,990 pounds. No boiler-brace should be allowed a greater stress 
than 6,000 pounds per square inch, measured at the smallest part. 
The number of braces required may be found by dividing the total 
load by what one brace will safely carry, which in this case is 45,990 
-i-6,000 = 7.65, say 8 braces; that is, it will require 8 braces having 
an area of 1 square inch, which corresponds to about 1J inches 
diameter. 

The surface or area supported by each brace is found by dividing 
. the whole area to be supported by the number of braces, which gives 



Fig. 65.—Gusset-brace. 


353.77-^8 = 44.22 square inches. The square root of this number 
will give the distance between the braces or the pitch, which is 6.64 
inches, or 6-]-^ inches. 

Table X gives the proper distance between the stays in a boiler for 
different maximum pressures. 

The table gives the size of stays corresponding to the several 
pressures when the stays run at right angles to the head, as at a in 
Fig. 64; but when they are placed at an angle, as at c, their holding- 
power for a given area of cross-section is considerably reduced, and 
in order to maintain the holding-power the area of the stays must 






















TYPES OF BOILERS 


73 


be increased. The required area of a diagonal stay may be obtained 
by dividing the area of the direct one by the cosine of the angle that 
the brace bears to the axis of the shell. 


Table X.—Direct Stays for Boilers. 


Diameter 
in inches. 

Area, 

square 

inches. 

Working 

strength. 

Number of inches square each brace will sustain 
under the following pressures: 

75 lbs. 

100 lbs. 

125 lbs. 

150 lbs. 


.60 

3,600 lbs. 

7. 

6. 

5.4 

4.9 

1 

.78 

4,712 “ 

7.9 

6.9 

6.1 

5.6 


.99 

5,964 “ 

8.9 

7.7 

6.9 

6.4 

H 

1.23 

7,362 “ 

9.9 

8.6 

7.7 

7.0 

if 

1.48 

8,880 “ 

10.7 

9.5 

8.5 

7.7 

11 

1.77 

10,620 “ 

11.9 

10.4 

9.2 

8.5 


The stresses in boilers and the constructive details, as to the 
strength of shells, seams, heads and braces, are given here as belong¬ 
ing to the special duties and practice of the engineer, as an inspector 
of the steam plant in his charge. 

There is much more that might be written in regard to the de¬ 
tails of boiler construction, which, for the information of engineers 
interested, we refer to works treating exclusively upon this subject. 




















CHAPTER V 


BOILER-CHIMNEY AND ITS WORK 


The power of a chimney to create draught depends somewhat 
on its form as well as height; but the main force of draught is in the 
difference of outside and inside temperatures. The ratio of wall-sur¬ 
face to its area is in evidence in the draught problem; and in 
general terms a round chimney is first in efficiency because its wall- 
surface is least in proportion to its area, the ratio being for equal 
areas about 13 per cent, greater wall-surface in a square chimney. 

Theoretically the strongest draught in a well-proportioned chim¬ 
ney is claimed to be obtained by a difference of absolute temperatures 
of 25 to 12, or when the atmospheric temperature is 60° and the 
chimney temperature 622° F. For internal chimney temperatures 
above 622° the densities of the gases decrease faster than the velocity 
increases, so that the weight of the gases passing up the chimney is 
at a maximum at about this temperature; but the draught-pressure 
increases with the height within reasonable limits. 


The effective area of a chimney varies inversely as the square 
root of the height, and is less than the actual area, owing to the friction 
of the gases against the walls, on the basis that this is equal to a 
layer of gas 2 inches thick on the wall-surface. The formula: 


Effectual area = 


0.3 H 


Fh 


also equals A — 0.6 FA, in which H is the 


boiler horse-power, h height of chimney, and A the actual area. Also, 
the boiler horse-poweiy of a chimney may be computed from the 
formula: H = 3.33EF^h, and the height for any horse-power from 
'0.3 H\ 2 

h = ( g— 1 , in which E is the effective area. 


The diagram, Fig. 66, shows the draught in inches of water for 
a chimney 100 feet high with different temperatures above the ex¬ 
ternal atmosphere, say 60° F. The vertical lines represent the 

chimney temperatures above 60° F. and the horizontal lines are 20 to 1 
74 





BOILER-CHIMNEY AND ITS WORK 


75 


inch. The upper curved line shows the ratio of the flow of gases at 
the various temperatures along the vertical lines in pounds per hour, 
which may be computed by multiplying the height of the curve at 
any given chimney temperature above that of the atmosphere by 



0 50 100 150 200 250 300 3 50 400 450 500 550 600 650 700 750 800 

Fig. 66.—Draught and weight of chimney-gases. 

the vertical scale in decimals of an inch, and by 1,000 times the ef¬ 
fective area in square feet, and by the square root of the height in 
feet. S 1,000E \/h. = pounds per hour, in which S = decimals of an 
inch on the vertical scale, E = effective area, and h=height of chimney. 
The pressure-curve in decimals of an inch of water is computed from 

( T 6 7 9\ 

-f-jH, in which h = height of chimney in feet, 

t a is the absolute temperature of the air entering the furnace, and t c 
the absolute temperature of the chimney-gases. 

For example, for a chimney 100 feet high with air and gas tem¬ 
peratures of 60° and 660° F., 100 hoQo - Vp>o°) = .7->G of an 
inch water-pressure. 

From this formula Table XI has been computed for external 
temperatures of from 10° to 90° F., and for chimney temperatures 
from 240° to 700° F. 

For any other height of chimney than 100 feet, the water-pressure 
will be approximately in proportion to the height, so that the pres¬ 
sures in the table columns at the junction of the external and chim¬ 
ney temperatures, multiplied by the decimal representing the pio- 
portion to 100 feet, will give the required water-pressure. 

For example, for the respective temperatures of 60° and 600° F., 
and 100 feet in height, 1.6X.716 = 1.14 inches water-pressure. 
































































76 


BOILER-CHIMNEY AND ITS WORK 


Table XI.—Draught-Pressure in Inches op 1 Water. 
In a Chimney 100 Feet High. 


Temper- 


Temperature of external air. (Barometer, 30 inches.) 


ature in 
chimney. 

10° 

20° 

O 

O 

CO 

o 

O 

50° 

0 

o 

o 

-4 

O 

o 

o 

O 

00 

90° 

240° 

.488 

.451 

.421 

.388 

.359 

.330 

.301 

.276 

.250 

260 

.528 

.484 

.453 

.420 

.392 

.363 

.334 

.309 

.282 

280 

.549 

.515 

.482 

.451 

.422 

.394 

.365 

.340 

.313 

300 

.576 

.541 

.511 

.478 

.449 

.420 

.392 

.367 

.340 

320 

.603 

.568 

.538 

.505 

.476 

.447 

.419 

.394 

.367 

340 

.638 

.593 

.569 

.530 

.501 

.472 

.443 

.419 

.392 

360 

.653 

.618 

.588 

.555 

.526 

.497 

.468 

.444 

.417 

380 

.676 

.641 

.611 

.578 

.549 

.520 

.492 

.467 

.440 

400 

.697 

.662 

.632 

.598 

.570 

.541 

.513 

.488 

.461 

420 

.718 

.684 

.653 

.620 

.591 

.563 

.534 

.509 

.482 

440 

.739 

.705 

.674 

.641 

.612 

.584 

.555 

.530 

.503 

460 

.758 

.724 

.694 

.660 

.632 

.603 

.574 

.549 

.522 

480 

.776 

.741 

.710 

.678 

.649 

.620 

.591 

.566 

.540 

500 

.791 

.760 

.730 

.697 

.669 

.639 

.610 

.586 

.559 

550 

.835 

.801 

.769 

.738 

.698 

.679 

.652 

.625 

.600 

600 

.872 

.838 

.806 

.775 

.735 

.716 

.689 

.662 

.637 

650 

.906 

.872 

.840 

.809 

.769 

.750 

.723 

.696 

.671 

700 

.936 

.902 

.870 

.839 

.799 

.780 

.753 

.726 

.701 


A simple form of draught-gauge is shown in Fig. 67. It consists 
of a small glass tube bent into a U shape, one-half filled with water, 

with a scale of tenths of an inch fixed between the 
legs; or the actual difference in level of the water 
may be measured when one of the legs is connected 
to the chimney by a tube. Usually a piece of J-inch 
iron pipe is passed through a hole in the main flue 
and connected to the gauge with a piece of rubber 
tube. 

The size and height of a chimney and its boiler 
horse-power depend upon the amount of coal assumed 
to be burned per horse-power, which requires a varia¬ 
ble size and height to meet the assumed economy of 
a steam-plant. 

Table XII is based on the average consumption of 
5 pounds of coal per hour per horse-power, which is 
assumed to be the maximum amount in any well- 
proportioned power-plant. For any less amounts of coal burned, a 
reduction in chimney height and area or an increase in the boiler- 



























































Table XII. —Size and Height of Chimneys for the Horse-Power Rating of Boilers. 


BOILER-CHIMNEY AND ITS WORK 


77 


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78 


BOILER-CHIMNEY AND ITS WORK 


horse-power columns may be made, proportionable to the amount 
of coal assigned per horse-power hour. 

For example, for a power-plant assumed to use but 2^ pounds of 
coal per horse-power hour, any boiler-power in the table may be 
divided by 2, and its amount compared with other chimney sizes and 
heights for selecting the required size and height of chimney. 

The formula by which the table has been computed is: Boiler 
horse-power = (3.33A—0.6 -/A) 4 /h, or 3.33E \Zh; E = A —0.6 4 /A; 

D = 13.54 i/E + 4; h = ( - ) ; S = 12i/E + 4, in which A = area of 

chimney in square feet; D = diameter in lhches; E = effective area; 
S = side of square chimney of equal effective area; h = height in feet; 
H = horse-power. 

Fig. 68 is an example of a steel chimney about 200 feet high, lined 
with brick, and anchored to a deep foundation by 12 long bolts 1J 
inches in diameter. It is 13 feet diameter inside and equal to a 
draught for 5,000 horse-power. 

Fig. 69 is an example of a brick chimney of varying dimensions 
suitable for a power-plant, as shown; it is subject to details suitable 
for any required power. 

The main point to be observed in the construction of a chimney 
after the height and internal diameter are fixed, is its stability or power 
to resist with safety the overturning force of the highest winds, 
which requires a proportionate relation between the weight, height, 
breadth of base, and exposed area of the chimney. This relation is 

d h 2 

expressed in the equation C —— = W, in which d = the average breadth 

of the shaft; h = its height; b = the breadth of base—all in feet; W = 
weight of chimney in pounds, and C = a coefficient of wind-pressure 
per square foot of area. This varies with the cross-section of the 
chimney, and = 56 for a square, 35 for an octagon, and 28 for a round 
chimney. Thus, a square chimney of average breadth of 8 feet, 10 
feet wide at base and 100 feet high, would require to weigh 56 X8 X 100 
X10 = 448,000 pounds to withstand any gale likely to be experienced. 
Brickwork weighs from 100 to 130 pounds per cubic foot; hence such 
a chimney must average 13 inches thick to be safe. A round stack 
could weigh half as much, or have less base. 






















































































































































































































































80 


BOILER-CHIMNEY AND ITS WORK 


The external diameter of a brick chimney at the base should be 
one-tenth the height, unless it be supported by some other structure. 
The “batter” or taper of a chimney should be from yg to } inch to the 
foot on each side. 

FIRING AND THE CHIMNEY- DRAUGHT 

The chimney-draught is one of the first things to be studied in 
the design of a power-plant, since upon it primarily depend the 
power and performance of the boilers. The amount of fuel that can 
be burned in a given time on a square foot of grate-surface depends 
on the strength of the draught, and draught, coal consumption, and 
efficiency are so closely allied that a discussion of one naturally brings 
in the others. If the draught is poor the fires have to be carried thin, 
and in this way a larger amount of air than is necessary for the combus¬ 
tion of the coal comes up through the grates; this excess air is not 
only useless, but it entails a loss by lowering the average temperature 
of the furnace, and the heat will not transfer to the water so rapidly. 
By careful nursing a heavy fire may be built up with a poor draught, 
but the average fireman is not a good nurse; he will either poke the 
fire or leave it alone, and his ideas of when to do these necessary parts 
of firing are generally as nearly right as are the ideas of many of 
those who try to show him how. Natural draught gives its best 
economy with a low rate of combustion, and as a general rule the 
fires should be carried as thick as the draught will burn without the 
fires having to be broken up more than once an hour. The stronger 
the draught, the more coal can be burned before the economical 
limit is reached. 

When forcing the fires with a strong chimney-draught there is the 
same loss as with thin fires and poor draught, namely, too much air 
per pound of coal burned, and another and greater loss, that of the 
increased temperature of the flue-gases to maintain the stronger 
draught; for after the temperature of the flue-gases exceeds 
600° F. it takes more heat to strengthen the draught. Under the 
conditions found in the ordinary plant with natural draught, the 
coal burned per square foot of grate-surface per hour averages from 
10 to 25 pounds, and the air used per pound of coal runs from 20 to 
30 pounds. Twelve pounds of air per pound of coal is all that is 


BOILER-CHIMNEY AND ITS WORK 


81 


required for its complete combustion, and the average plant uses 
nearly twice this amount. Anything that will cut down the amount 
of air used per pound of coal will effect a saving. The most that can 
be saved in this way is about 5 per cent, of the coal. 

With natural draught the only way of limiting the amount of ab¬ 
used is by keeping thick fires. But thick fires are apt to be neglected, 
because the fireman knows that if the steam gets down he can stir up 
the fires and have it right up again, while he would manage thin fires 
in a better manner, because he cannot take any chances with them. 
Furthermore, there are some kinds of coal which lie on the grates 
like sand, and it is impossible to get enough draught with a chimney 
to burn a thick fire of such coal. 

This brings us to a consideration of some of the kinds of forced- 
draught apparatus. When speaking of forced draught the general 
idea is that the air supplied by a fan or other apparatus will cause a 
higher rate of combustion of the coal than is possible with the rare¬ 
faction of air in a chimney. This was the practice at first, but forced 
or induced draught is now used for all rates of combustion. When 
coal is dear more attention is paid to ways of burning cheap coal 
economically, for some of these coals will evaporate nearly as much 
water as high-priced coal, and cost less than half as much. The 
cheapest apparatus for this purpose is some form of steam-jet, 
either one that produces a partial vacuum in the chimney, as in 
a locomotive, or one that blows into a closed ash-pit and carries 
a large body of air in with the steam. 

But on account of the large amount of 
steam required for operation, a steam- 
jet is only advisable where fuel is very 
cheap. 

In Fig. 70 is illustrated one of many 
models of steam-jet blowers, with an 
annular cast-iron chamber perforated Fig. 70.—Annular steam-blower, 
for steam-jets at an angle that projects 

the jets in a converging direction that draws in the air with a force 
corresponding with the pressure of the steam. This class of blowers 
are much in use and are connected with the ash-pit and in short 
chimneys at their base. 

































82 


BOILER-CHIMNEY AND ITS WORK 


In Fig. 71 is illustrated one of the Korting type of steam-blowers, 
with a double-nozle air-inlet and double-cone nozle for steam. A 
needle-valve regulates the flow of steam from the central jet, which 



Fig. 71.—Korting steam-blower. 


is reenforced by the combined steam and air in the larger nozle, by 
which a larger volume of air is induced and expanded in the 
diverging-nozle. 

In Fig. 72 is illustrated a low-speed fan-blower of large volume 
and force. Its particular feature is in the narrow curved blades set in 
the periphery of the wheel and close together, which prevent local 
eddies and greatly increase the efficiency of the fan. 

A well-designed forced-draught fan will run with less than 1 per 
cent, of the steam supplied to the engines, while the amount of heat 


A 



Fig. 72.—Sirocco fan-blower. 

that a chimney requires for its operation will be equal to 30 per 
cent, of the steam supplied to the engines. Practically it is impos¬ 
sible to save this 30 per cent., on account of the cost of apparatus 
for reducing the temperature of the flue-gases to that of the air enter- 





















































































































BOILER-CHIMNEY AND ITS WORK 


83 


ing the ash-pit. The first saving a fan-draught will make is in the 
lessened amount of air per pound of coal. A number of tests have 
been reported where the air supplied was less than 15 pounds to each 
pound of coal. The temperature of the furnace with a lessened air- 
supply will be higher; and the heat will be more quickly transferred 
from the gases to the water of the boiler. The gases will travel more 
slowly over the heating-surface, and the temperature of the chimney- 
gases will be lower. Economizers placed between the boilers and the 
chimney will heat the feed-water and save more than enough to pay 
for themselves in a short time. 

The use of hot air for the furnace effects a saving in fuel, and with 
a fan-forced draught taking the air from the ceiling or roof of the 
boiler- or engine-room, where it is often at a temperature above 
100 ° F., makes a saving of from 10 to 20 per cent, of the coal over the 
waste from a low natural draught, besides the comfort of a modified 
temperature of the room. A fan should be large enough to furnish 
the required amount of air at as moderate a speed as will give the 
proper pressure, for the power to drive a fan increases as the cube 
of the speed. 

A fan, the tips of its blades running at 65 feet a second, will give a 
draught of 1 inch of water. If possible, coal should not be burned 
with a stronger draught than this, for with a stronger draught the fires 
need very careful watching to prevent holes from burning through 
and letting in too much air, although mechanical stokers which have 
a constant-feeding attachment may have as much as 3 inches of 
draught without affecting the economy, for a strong draught will 
force the air through a heavy fire in more intimate contact with the 
fuel, and in this way be an aid to perfect combustion. A draught 
of J inch of water is about as low as it is possible to obtain complete 
and smokeless combustion. With this amount of draught from 12 
to 20 pounds of coal per hour per square foot of grate-surface may 
be burned. 


CHAPTER VI 


HEAT-ECONOMY OF THE FEED-WATER 

The saving of heat that would otherwise be w-asted or lost by the 
exhaust-steam and the chimney-g^ses is of great consideration in the 
economy of steam-power. The exhaust-steam water-heater and the 
chimney-heat economizer are the only real saving devices that affect 
the cost of fuel. The live, steam heaters free the water from its 
incrusting elements, and injectors are only convenient mechanical 
substitutes. The following table shows the saving in percentage of 
the total fuel used by heating the feed-water between various initial 
and final temperatures: 


Table XIII. —Percentage of Saving in Fuel by Heating Feed-Water. Steam 

at 70 Pounds Gauge-Pressure. 


& & 

S 3 • 
i -n "C 
o3 0> 









Temperature to Which 

Feed 

IS 

Heated. 








.2 ^ <D 
• <— Q. 

G 

HH 

100° 

110° 

120° 

1 

30° 

140° 

150° 

160° 

170° 

180° 

190° 

200° 

210° 

220° 

250° 

300° 

35° 

5 

53 

6 

38 

7 

24 

8 

.09 

8. 

95 

9 

89 

10 

66 

11 

52 

12 

38 

13 

24 

14 

09 

14 

95 

15 

81 

19 

40 

29 

34 

40° 

5 

12 

5 

97 

6 

84 

7 

.69 

8. 

56 

9 

42 

10 

28 

11 

14 

12 

00 

12 

87 

13 

73 

14 

59 

15 

45 

18 

89 

28 

78 

45° 

4 

71 

5 

57 

6 

44 

7 

30 

8. 

16 

9 

03 

9 

90 

10 

76 

11 

62 

12 

49 

13 

36 

14 

22 

15 

09 

18 

37 

28 

22 

50° 

4 

30 

5 

16 

6 

03 

6 

89 

7. 

76 

8 

64 

9 

51 

10 

38 

11 

24 

12 

11 

12 

98 

13 

85 

14 

72 

17 

87 

27 

67 

55° 

3 

89 

4 

75 

5 

63 

6 

49 

7. 

37 

8 

24 

9 

11 

9 

99 

10 

85 

11 

73 

12 

60 

13 

48 

14 

35 

17 

38 

27 

12 

60° 

3 

47 

4 

34 

o 

21 

6 

08 

6. 

96 

7 

84 

8 

72 

9 

60 

10 

47 

11 

34 

12 

22 

13 

10 

13 

98 

16 

86 

26 

56 

65° 

3 

05 

3 

92 

4 

80 

5 

.67 

6. 

56 

7 

44 

8 

32 

9 

20 

10 

08 

10 

96 

11 

84 

12 

72 

13 

60 

16 

35 

26 

02 

70° 

2 

6? 

3 

50 

4 

38 

5 

.26 

6. 

15 

7 

03 

7 

92 

8 

80 

9 

68 

10 

57 

11 

45 

12 

34 

13 

22 

15 

84 

25 

47 

75° 

2 

19 

3 

07 

3 

96 

4 

.84 

5. 

73 

6 

62 

7 

51 

8 

40 

9 

28 

10 

17 

11 

06 

11 

95 

12 

84 

15 

33 

24 

92 

80° 

1 

76 

2 

65 

3 

54 

4 

.42- 

5. 

32 

6 

21 

7 

11 

8 

00 

8 

8 

9 

78 

10 

67 

11 

57 

12 

46 

14 

81 

24 

37 

85° 

1 

30 

2 

22 

3 

11 

4 

.00 

4. 

90 

5 

80 

6 

70 

7 

59 

8 

48 

9 

38 

10 

28 

11 

18 

12 

07 

14 

32 

23 

82 

90° 

0 

89 

1 

78 

2 

68 

3 

.58 

4. 

48 

5 

38 

6 

28 

7 

18 

8 

07 

8 

98 

9 

88 

10 

78 

11 

68 

13 

82 

23 

27 

95° 

0 

45 

1 

34 

2 

25 

3 

.15 

4. 

05 

4 

96 

5 

86 

6 

77 

7 

66 

8 

57 

9 

47 

10 

38 

11 

29 

13 

31 

22 

73 

100° 

0 

00 

0 

90 

1 

81 

2 

.71 

3. 

62 

4 

53 

5 

44 

6 

35 

7 

25 

8 

16 

9 

07 

9 

98 

10 

88 

12 

80 

22 

18 


The feed-water furnished to steam-boilers has to be heated from 
the normal temperature to that of the steam before evaporation can 
commence, and this generally at the expense of the fuel which should 
be utilized in making steam. This temperature at 75 pounds pressure 
is 320° F., and if we take 60° F. as the average temperature of feed, 
we have 260 units of heat per pound, which, as it takes 1.151 units to 

evaporate a pound from 60° F., represents 22.5 per cent, of the fuel. 

84 








































HEAT-ECONOMY OF THE FEED-WATER 


85 


All of this heat therefore which can be imparted to the feed-water is 
just so much saved, not only in cost of fuel but in capacity of boiler. 
Hut it is essential that it be done by heat which would otherwise be 
wasted. All heat imparted to feed-water by injectors and live-steam 
heaters comes from the fuel and represents no saving. 


The number ol square feet of surface required in feed-water 
heaters, for each horse-power, assuming an abundance of exhaust- 
steam is available, may be found by the following formula: S = .227 



in which S = square feet of tube-surface per horse-power, 


or the surface required to heat 34.5 pounds per hour; T s = tempera¬ 
ture of the steam; T x = temperature of the water entering the heater, 
and T 2 = the temperature of the water leaving the heater. The horse¬ 
power of heater per square foot of surface is 1-eS. The result 
obtained by the use of the formula should be multiplied by 1.12 for 
brass tubes and by 1.67 for iron tubes. 

Table XIV gives the tube-surface in square feet required to heat 
34.5 pounds of water per hour, or for each boiler horse-power. 


Table XIV.—Area of Heating-Surface Required in Feed-Water Heaters 
per Boiler Horse-Power, 34 b Pounds per Hour. 


Temperature of Boiler-Feed. 


Initial 

temper¬ 

ature. 


170° 



180° 



190° 



200° 


Copper. 

Brass. 

Iron. 

Copper. 

Brass. 

Iron. 

Copper. 

Brass. 

Iron. 

Copper. 

Brass. 

Iron. 

50° 

.15 

.17 

.24 

.20 

.23 

.34 

.22 

.24 

.36 

.29 

.32 

.46 

60° 

.14 

.16 

.23 

.19 

.22 

.33 

.21 

.23 

.35 

.28 

.31 

.45 

70° 

.13 

.15 

.22 

.18 

.21 

.31 

.20 

.22 

.34 

.27 

.30 

.44 

80° 

.12 

.14 

.21 

.17 

.20 

.29 

.19 

.21 

.32 

.26 

.29 

.43 

90° 

.11 

.13 

.19 

.16 

.18 

.28 

.18 

.20 

.30 

.25 

.28 

.41 

100° 

.10 

.12 

.17 

.15 

.17 

.26 

.17 

.19 

.29 

.24 

.27 

.40 

110° 

.09 

.10 

.16 

.14 

.16 

.24 

.16 

.18 

.27 

.23 

.26 

.38 

120° 

.08 

.09 

.14 

.13 

.15 

.22 

.15 

.17 

.25 

.22 

.24 

.36 

130° 

.07 

.08 

.12 

.12 

.13 

.20 

.14 

.15 

.23 

.21 

.23 

.34 


The extent of heating-surface given in the table for 1 horse-power 
will generally be found ample for coil-heaters and for horizontal 
double-flow water-tube heaters having copper coils and copper tubes 
respectively, and for vertical water-tube heaters with corrugated 
copper tubes when the aggregate tube-area corresponding to the direc¬ 
tion of flow is not large, thus insuring a more rapid circulation. 











































86 


HEAT-ECONOMY OF THE FEED-WATER 


FEED-WATER HEATERS 

Feed-water heaters are made of both the closed and open types. 
In the closed type the water is caused to circulate through tubes 
arranged in different ways, while the exhaust-steam envelops the 
tubes from end to end in passing from the inlet to the outlet. In 
other heaters of the closed type t^e water is outside and the steam 
inside the tubes. The former method of heating, however, is the 
better, because a positive and more rapid circulation of the water is 
thus secured; and it has been found that the efficiency of a feed-water 
heater depends largely upon proper circulation, the absorption of 
heat taking place more rapidly with a brisk circulation than when the 
circulation is sluggish. Horizontal tubes frequently give somewhat 
better results for a given area of heating-surface than do vertical 
tubes, but the slight loss due to the position is fully compensated 
for in the vertical types by allowing slightly more surface and caus¬ 
ing the water to flow from top to bot¬ 
tom against the current of steam, so that 
it makes but little difference in practice 
whether a horizontal or vertical heater is 
selected, as far as being able to heat water 
to the desired temperature is concerned. 

When certain constructions of closed 
heater are employed, notably the coil, a 
somewhat smaller heater may be used, 
owing to the positive and rapid circulation 
and the efficient form and arrangement of 
the heating-surfaces. The closed heater 
is also adapted to use with condensing- 
engines. Either type may be successfully 

Fig. 73.— Multicoil-heater. employed in connection with heating sys- 

terns, the shells being made of ample 
strength to resist the pressures generally employed in heating by 
exhaust-steam. The temperature of the water leaving the heater is 
usually about the same with both the closed and open types under 
the same conditions. The shells and pipes should be covered with 
some non-conducting material to prevent radiation, so that as much 






















































HEAT-ECONOMY OF THE FEED-WATER 


87 


steam as possible may be provided tor other purposes when the steam 
is to be utilized after passing through the heater. 

The open heater is not necessarily subjected to any pressure 
either of steam or water except that due to the weight of the 
water it contains. This type of heater furnishes a settling-chamber 
for the impurities in the feed-water, which with muddy water, or 
water containing large quantities of other impurities, is of great ad¬ 
vantage. By introducing suitable trays or pans a considerable 
quantity of scale-making material may also be removed, while the 
condensation of a portion of the steam furnishes a certain amount 
of pure water, which is added to that in the heater. One of the 
greatest difficulties formerly experienced with open heaters was 
found in avoiding the effects of the cylinder-oil carried into the heater 
by the exhaust-steam. In but few cases at present is this difficulty 
experienced, the construction being such as to exclude the greater 
part of the oil, and to give the water sufficient time in the heater to 
permit the remaining oil to rise to the surface of the water and be 
drained off through suitable waste-pipes. When selecting an open 
heater it is important to investigate the provisions made for disposing 
of the oil and preventing it from entering the boiler. The open 
heater should be so constructed as to permit easy and frequent cleans¬ 
ing, when necessary, and the ready removal of the filtering material 
and of pans or trays when these are employed. 

The open feed-water heater is designed so that the water entering 
at the top will be finely divided and will fall through the reservoir of 
steam in the form of a fine spray or a very thin film, thus bringing 
practically all the water into close contact and causing an intimate 
commingling with the steam in the shortest time possible, that is 
when considering the total time required for the water to pass through 
the heater. The time during which the water is passing downward 
from the inlet to the water-reservoir at the bottom is, however, made 
as long as possible so as to secure the thorough absorption of the heat 
in the steam, for upon the thoroughness of this process depends the 
temperature to which the water can be heated with a given initial 
temperature and a given temperature of steam. 

In Fig. 74 is a sectional view of the Berryman heater, in which the 
exhaust-steam passes through the inverted U-shaped tubes, which 


88 


HEAT-ECONOMY OF THE FEED-WATER 


permits both ends of the tubes to be expanded into the same tube- 
sheet, and thus they cannot be affected by expansion or contraction. 
Each tube is absolutely independent of every other tube. They 

seldom coat or scale, and thus their full 
heating-surface is indefinitely maintained. 

The head into which the tubes are set is 
cast-iron, from 2 to 3 inches in thickness. 
The holes for receiving the tubes are first 
drilled the size of the inside of the tubes, 
then counterbored to within J inch of the 
bottom of the tube-head, leaving a solid 
shoulder on which the tube rests. A groove 
is cut in the centre of the bore of the thick¬ 
ness of the tube. The U-shaped tubes are 
then expanded in these grooves, their shape 
preventing any strain from expansion or 
contraction, which, together with the man¬ 
ner of setting them, prevents leaking or 
getting loose. 

The tube-head is concave, and at its 
lowest point a mud blow-off is arranged, 
through which the sediment and other impurities can be removed. 
It should be opened for a few seconds as often as the condition of the 
water necessitates, which can readily be determined by experiment. 

The exhaust-steam enters at one side of the heater, passes up 
through the tubes and down and out on the other side. The ports 
in the heater may be arranged to meet the needs in any case. 

The water enters the heater at the side, but at a sufficient distance 
from the bottom to prevent disturbing the sediment which has col¬ 
lected. 

The water leaves the heater through a pipe which extends down 
a few inches from the top, and is thus taken at the hottest part. 

The Wainwright heater, Fig. 75, has the advantage derived from 
the tubes being corrugated, which not only gives increased surface 
to the tubes, but makes them elastic, and thus insures their tightness 
in the tube-heads. There is an ample settling-chamber at the bot¬ 
tom and a surface blow-off and storage-room at the top. The tubes 



Fig. 74.—Berryman heater. 














































































































HEAT-ECONOMY OF THE FEED-WATER 


89 


occupy only one-fourth of the shell-area, and the net shell-area is at 
least three times as large as the area of the exhaust-pipe. This allows 
the steam to flow freely about the small columns of moving water. 

The water-chambers are divided into several compartments, and 
the partitions are so arranged that they direct the flow of the feed- 
water back and forth through the heater, using the various groups of 
tubes in succession, with a consequent increase in velocity over that 
.obtained in the non-return type of heater. Each of these groups 
of tubes contains a sufficient number of tubes to give a sectional 



Fig. 75. —Wainwright 
heater. 



Fig. 76.—Cookson heater, purifier, 
and oil-separator. 


area which is at least twice the sectional area of the feed-pipe. This 
increase in the speed of the feed-water brings all parts of it into con¬ 
tact with the heating-surface and insures a uniform use of all the 
tubes. Experiments have shown that in some constructions of multi¬ 
tubular heater the water may remain almost stagnant in a portion 
of the tubes. The practical result is that there is offered in the even 
flow a heater with which there can be a very high final temperature, 
approximating 212° F. under ordinary conditions of exhaust with non- 
condensing-engines. 

In the Cookson heater, Fig. 76, the steam enters the side and strikes 
the V-shaped, oil-separating plates which divide the volume of steam, 



































































































































































































90 


HEAT-ECONOMY OF THE FEED-WATER 


the ribs on the plates catching the oil and moisture in the steam. 
The steam then enters the enlarged portion of the exhaust-tube, 
where it passes into the opposite expansion and oil-separating cham¬ 
ber and discharges into the atmosphere or 
heating system. At the top of the heater 
is a vent-pipe for carrying off the air re¬ 
lieved from the water in heating. The 
vent-pipe is to be connected with the 
exhaust-outlet. The cold-water supply en¬ 
ters in a spray and condenses the steam, 
forming a partial vacuum, which draws 
the required amount of steam to heat the 
water through the large tube in the centre. 
Only that amount of steam necessary to 
heat the water comes in contact with it, 
the remainder passing on to the heating 
system or the atmosphere. 

The water-supply is connected with the 
water-inlet valve, which is opened and 
closed by the water-regulator, maintaining 
at all times a uniform water-level in the heater. The water entering 
the spray-box at the top of the heater overflows in a spray to the pan 
below, and, overflowing this pan, falls in a spray into the next. The 
water passes from this third pan over its outer edge, following down on 
the under side to the next pan below, and so on down. The last pan 
is bolted to the top of the exhaust-tube. The water sprays from 
this last pan to the water below. All pans, with the exception of 
the bottom one, are loose, made in halves, and are readily removed 
through the man-hole. The object of these pans is to catch the lime 
deposits. The water, after having been heated in direct contact 
with the steam, enters the hollow partition at the back of the exhaust- 
tube. The water discharges from the hollow partition near the front 
into the filtering-chamber below, where the remaining impurities in 
suspension are removed by filtration. The filtering-chamber is filled 
with coke or excelsior, and at the back of this chamber is a perforated 
plate preventing the filtering material from passing through to the 
pump. A strainer-plate is also placed at the blow-off connections. 
The blow-off and oil-discharge pipes are placed on the side opposite 



Fig. 77.—Feed-water heater 
and filter. 


































































































HEAT-ECONOMY OF THE FEED-WATER 


91 


the exhaust-inlet. The two oil-separating chambers are connected 
by a small opening through the hollow partition at the bottom, 
through which the oil and condensed steam drain, passing from 
there into the oil-discharge pipe and thence to the sewer. 

In the feed-water heater and filter, Fig. 77, the exhaust-steam 
enters at the bottom and flows into the first compartment through 
a short pipe, thence through the annular opening surrounding the 
second compartment into the latter, thence through another annular 
opening into the next compartment. After passing through the 
annular openings the steam comes in contact with baffle-plates, which 
direct the steam through the falling water and condense it. A ring- 
pipe at the top distributes the water upon a baffle-plate, from which 
it falls upon the top filter and so on through the three filter sections. 

The Hoppes standard feed-water heater, shown in Fig. 78, is sup¬ 
plied with pans of the same design as those in the live-steam, feed- 
water purifier. The water in flowing over the sides and bottoms 



of the pans comes in direct contact with the steam and is heated 
nearly to the temperature of the exhaust-steam. 

This heater is especially designed to be used where the water is 
bad, and one peculiar advantage is had in the fact that the water 
flows along the under side of the pans, or the lime formation thereon, 
and thus comes in direct contact with the exhaust-steam, no matter 
how thick the lime formation may be on the pans. The appar atus 
is provided with a large oil-catcher, located in the rear, and thiough 
which all the steam passes and is purified before entering the heater. 





























92 


HEAT-ECONOMY OF THE FEED-WATER 


A float is provided which operates a balanced valve for the regulation 
of the feed-water. The entire front head is easily removed and 
swung to one side by a crane provided for this purpose, so that the 
pans may be readily removed. As the pans contain all of the lime 
and other solids formed in the heater, the entire work of cleaning is 
performed outside of the heater. # 

THE GREEN FUEL-ECONOMIZER 

This apparatus consists of a stack of tubes arranged vertically in 
the flue leading from the boiler to the chimney (as illustrated in Fig. 
79), and is designed to utilize the waste heat in the gases passing off 
from the furnace. This is accomplished by absorbing the low-tem¬ 



perature heat of the gases in heating the feed-water, which is pumped 
through the economizer before entering the boiler. The waste gases 
are led to the economizer by the ordinary flue from the boilers to the 
chimney. 

The feed-water is forced into the economizer by the boiler feed¬ 
pump, or an injector, at the lower branch pipe nearest the point of 
exit of the gases, and emerges from the economizer at the upper 
branch pipe nearest the point where the gases enter. 






































































































































































































































































































HEAT-ECONOMY OF THE FEED-WATER 


93 


Each tube is provided with a geared scraper, which travels con¬ 
tinuously up and down the tubes at a low rate of speed, the object 
being to keep the external surface clean and free from soot. 

The mechanism for working the scrapers is placed on the top of 
the economizer, outside the chamber, and is very simple and effective; 
the motive power is supplied either by a belt from some convenient 
shaft or by a small independent engine or motor. The power required 
for operating the gearing is very small. 

The apparatus is fitted with blowoff- and safety-valves, and a 
space is provided at the bottom of the chamber for the collection of 
the soot removed by the scrapers. 

The scrapers are three in number and encircle the pipes with the 
joints overlapping one another. They have thin, beveled cutting- 
edges which entirely remove any accumulation of soot. Under 
conditions where a forced circulation may be an advantage, circu¬ 
lating blow-off manifolds are introduced. By means of these mani¬ 
folds any portion or the whole of the economizer can be made to cir¬ 
culate, and at the same time every section can be thoroughly blown 
off. As the economizer should be blown off for a few moments at 
least once a day, the valves are connected together by a long lever, 
which makes the operation very simple and takes the least possible 
time to operate. 


CHAPTER VII 

THE INJECTOR AND THE STEAM-PUMP 


The injector and its theory were matters of much discussion 
during the early years of its use, and its final solution has been mathe¬ 
matically demonstrated as the elimination of the volume of the 
steam-jet at a high velocity by the instantaneous absorption of its 
latent heat in contact with the incoming water, thus imparting its 
velocity momentum to the water around it, by which interchange of 
temperatures the volume of the steam is reduced to the volume of 
its water-base. By this action its proportionate velocity is imparted 
to the incoming annular water-jet, which becomes a solid water-jet 
at the end of the combining-nozle, the momentum of which is far 
greater than is required to overcome the resistance of the boiler- 
pressure, and the jet crosses a starting relief-space and enters the 
delivery-nozle, opening by its force the boiler check-valve. 


The formulas representing the action of an injector are as follows: 
For the velocity of the injection at the exit of the combining-nozle 
we have, A' = 12.19 V p in feet per second, in which p = the gauge-press¬ 
ure. The volume of water and condensed steam passing the nozle 
of the combining-tube, per second, will be 0.016 (W + W 0 ); and if A 
be the area and W the weight of the steam, and W 0 the weight of the 


water, then 


A = 0.016 (W + Wq) 
V 


in which V = velocity, as found above. 


The velocity of the steam may be found from the formula: 


V = 23.2687 



in which p = absolute initial 


pressure, v = volume of steam at initial pressure, and p 2 = pressure in 
the chamber between the nozles—generally atmospheric pressure. 

Table XV is an approximate service of a simple injector, equal 
to the delivery of about 1 pound of water per second at a tempera¬ 
ture of 160° F. from feed-supply at 60° F. 

94 




THE INJECTOR AND THE STEAM-PUMP 


95 


Table XV.—Gauge-Pressures, Nozle-Diameters, and Velocities of Steam and 

Water and Their Ratios. 


Gauge- 

pressure, 

pounds . 

Diameter 

steam- 

nozle, 

inches. 

Diameter 

water- 

nozle, 

inches. 

Velocity 
steam, 
feet per 
second. 

Velocity 
steam and 
water, feet 
per 

second. 

Ratio of 
velocity 
steam to 
water. 

Ratio of 
weight, 
water to 
steam. 

Ratio of 
volume, 
steam to 
water. 

30 

0.28 

0.21 

2007.9 

66.7 

30 . 

10.3 

55.9 

40 

0.24 

0.20 

2178.8 

77.1 

28 . 

10.3 

46.2 

50 

0.22 

0.19 

2213.5 

86.2 

25 . 

10.4 

39.4 

GO 

0.20 

0.18 

2428.8 

94.4 

25 . 

10.5 

34.4 

70 

0.18 

0.178 

2522.3 

101.2 

25 . 

10.5 

30.4 

80 

0.17 

0.172 

2554.1 

108.0 

24 . 

10.5 

27.6 

90 

0.167 

0.166 

2590.6 

115.6 

22 . 

10.5 

25.2 

100 

0.159 

0.160 

2735.8 

121.8 

22 . 

10.5 

22.8 

120 

0.142 

0.154 

2842.7 

133.5 

21 . 

10.6 

19.6 

140 

0.133 

0.149 

2922.3 

144.2 

20 . 

10.6 

17.2 

160 

0.127 

0.143 

2999.7 

154.2 

19 . 

10.6 

15.3 


Under ordinary conditions an injector will feed about 12 pounds 
of water to a boiler per pound of steam, or 13 pounds including its own 
weight. 

The limit of the feed-water temperature for an injector is about 
110° F., so that open feed-water heaters cannot supply the water; 
but injectors can feed boilers through closed heaters to advantage, 
with possibilities of raising the temperature of the feed-water to near 
212° F. 



TO BOILER 


STEAM 


CHECK VALVE 


• VALVE 
S SEAT 


OVERFLOW 


WATER 


Of the many models of injectors on the market, the tandem and 
double combining-tube models are taking the lead for efficiency and 
reliability. Following are illus¬ 
trated some of the various 
models in section, showing 
their details of construction: 

The Penberthy injector, Fig. 

80, special model, has three 
fixed nozle-tubes in line. The 
opening of a detached valve 
gives steam to the chamber E 
through the annular orifice be¬ 
tween the combining- and re- 
ceiving-nozles at F, and by its pressure opens the relief check- 
valves C and D. When the water-current is established, the pressure 


Fig. 80.—Penberthy injector. 


in the chamber next to the boiler check-valve closes the check-valve 

































































96 


THE INJECTOR AND THE STEAM-PUMP 


D, which by the contact of its wings with the check-valve C closes it, 
and the full pressure opens the boiler check-valve. 

The Little Giant, Fig. 81, is an adjustable injector in which two of 
its three tubes are fixed. The combining-tube is movable for adjust¬ 
ment by the lever-handle, wlfich by drawing the combining-tube 

toward the steam-nozle regu- 


STEAM 



lates the flow of water, and the 
steam is regulated by a de¬ 
tached valve. The relief check- 
valve C automatically closes on 
the establishment of the water- 
current. 


Fig. 81.— Little Giant injector. 


The Lunkenheimer injector, 
Fig. 82, has four fixed nozle- 
tubes, with all the valves required for operating it attached to the 
injector. The steam-regulating valve is adjusted by a lever as shown; 
D is the stop-check to the overflow, which is carried around the body 
of the injector to the nozle below. In starting, the pressure, by the 
escape of steam at the annular orifice into the chamber E, opens the 
relief-check C. When the water-current is established, the overflow- 
check at D is closed, and the pressure from the nozle of the second 
section of the combining-tube 


in the chamber S closes the 
check-valve C, and the water 
and steam pass this gap in a 
solid stream. 


Of the tandem nozle-injec- 
tors there are a great variety 
of models on the market, each 
having its own peculiar feat¬ 
ures. The double-tube injec¬ 
tors, although seemingly some- 



i « 

Fig. 82.—Lunkenheimer injector. 




what more complex in their construction, are claimed to deliver the 
feed-water at a higher temperature by the fact that the water passes 
successively through two combining-nozles. 

As an example of this class we illustrate in section, in Fig. 83, the 
Metropolitan double-tube injector. 





























































THE INJECTOR AND THE STEAM-PUMP 


97 


The steam is turned on from a separate valve; the first movement 
of the handle opens the first section of a double-beat valve at b ; and 
gives the steam to the lifting- 
nozle A; the overflow passing 
freely through the check-valve 
C and the open valve at D. A 
further movement of the handle 
opens the second section of the 
double-beat valve B, and closes 
the overflow-valve D, when the 
flow of warm water from the first 
tube, M, flows into the chamber 
F, and to the second tube, and 
through the chamber G to the boiler. The pressure in G at the mo¬ 
ment of discharge of the second tube closes the overflow-valve C. 



Fig. 83.—Metropolitan injector. 


The Korting injector, Fig. 84, is of the double-tube variety, with 
an automatic movement by which the difference in area of the valve- 
disks at A and B allows the balance-lever to open the lifting-nozle 
first, and by a further movement of the handle opens the force- 
nozle B. The overflow is self-adjusting for both nozles. 


The real efficiency in the injector, and its economy in saving part 
of the heat lost by the exhaust, are found in the exhaust-injector 



Fig. 84.—Korting injector. 



Fig. 85.—Exhaust-injector. 


(shown in Fig. 85) of the triple-tube model, in which the centre or 
combining-tube has a hinged section which opens automatically by 




































































98 


THE INJECTOR AND THE STEAM-PUMP 


the incoming exhaust, and allows a free flow to draw the water into 
the nozle and through the overflow. When the water-current is 
established the hinged section of the combining-tube automatically 
closes, and the injector operates the same as others for feeding a 
boiler. The portion of the exjiaust not used by the injector may 
pass through a heater which the injector feeds, thus increasing the 
feed-water temperature. 

The efficiency of the injector as a heat device is claimed to be 
theoretically perfect, as it returns all the heat it receives from the 
boiler save the radiation and the small losses in starting; but as a 
pump for elevating water its efficiency is very low in comparison with 
the steam-pump, being about one-fifth as efficient. The work of forcing- 
water into a boiler, say at 80 pounds pressure, in the proportion of 13 
pounds of water to 1 pound of steam, as shown in Table XV, is, 144 X 
80X13X0.016 = 2,396 foot-pounds. One pound of steam in the 
direct-acting steam-pump will, at 80 pounds boiler-pressure, do the 
actual work of 10,000 foot-pounds, or over four times as much as an 
injector. A pump feeding a boiler at 80 pounds pressure which 
generates 8J pounds of steam per pound of coal consumes about 2 
per cent, of the fuel. 

THE STEAM-PUMP AND ITS WORK 

The power required to force water against a given pressure or 
height must include in its resistance the height of the draught or 
suction and the friction of the pump as a machine, as the three static 
elements against which the pump must work; and also the element 
of action to keep the pump moving at the required speed. The 
friction and action elements of pump-work, especially in small pumps, 
may be as much as 60 per cent, greater than the total static force of 
the pump’s work. 

In pumps used for boiler-feeding with pressure-supply, the usual 
ratio of diameter of steam-cylinder to water-cylinder is from 1.20 to 
1.25; but where extreme suction-lift has to be overcome, a ratio of 
1.30 is a safer assurance of proper action, and in such cases only 
pumps with very small clearance can be relied upon. 

The formulas for the balance of pressure and areas in steam- 
pumps, to which should be added the necessary steam-pressure for 
actuating the pumps, are: 


THE INJECTOR AND THE STEAM-PUMP 


99 


water-pressure 

- -—t---—t— = steam-pressure. 

area steam - cylinder -r- area water - cylinder 

area water-cylinder X water-pressure 


area steam-cylinder 

water-pressure area steam-cylinder 
steam-pressure area water-cylinder 
area steam-cylinder X steam-pressure 
water-pressure 

area steam-cylinder X steam-pressure 
area water-cylinder 


= steam-pressure. 


= area water-cylinder. 


= water-pressure. 


For obtaining the actual horse-power that is required to operate 
a pump, we have weight of water in pounds per minute X height (or 
pressure X2.3) -4- 33,000 = horse-power. 

The decreasing pressure of the atmosphere at a height above sea- 
level materially affects the suction-lift of a pump. Assuming that 
the practical lift of a pump at sea-level is 25 feet, the following table 
shows the comparative height, pressures in pounds, and equivalent 
head of water in feet, and the corresponding practical lift of pumps: 


Table XVI.—Height and Atmospheric Pressure, with Equivalent Head of 

Water and Pump-Lift. 


Altitude Above Sea-Level. 

Pressure, pounds 
per square inch. 

Equivalent head 
of water, feet. 

Practical suction- 
lift in feet. 

At sea-level . 

14.70 

33.95 

25. 

I mile = 1,320 feet. 

14.02 

32.38 

24. 

\ “ - 2,640 “ . 

13.33 

30.79 

23. 

f “ - 3,960 “ . 

12.66 

29.24 

21. 

1 “ - 5,280 “ . 

12.02 

27.76 

20. 

H “ - 6,600 “ . 

11.42 

26.38 

19. 

“ - 7,920 “ . 

10.88 

25.13 

18. 

2 “ -10,560 “ . 

9.88 

22.82 

17. 


In the ordinary practice of piping pumps for feeding boilers the 
friction of the water in the pipes is not considered; but sometimes 
long suction-pipes are required, when the friction may be seiious, 01 
an obstacle to high lifts. Five hundred to 1,000 feet aie feasible dis¬ 
tances for pump-suction with an ample air-chambei on the sik t ion-pipe 
near the pump and with lifts as in the table, less the friction-head for 

pipe and fittings. 
































100 


THE INJECTOR AND THE STEAM-PUMP 


The formula for straight pipe is: 


T 4 V 2 ZV _ 9 

— x-——-- = friction-head in feet. 

d 1,200 


L = length in feet; d = diameter in inches; V = velocity of the water 
in feet per second. An elbow is equal to 60 diameters, and a globe- 
valve equal to 90 diameters., of th^ pipe, and should be added to the 
length of the pipe. 

Of the many models of boiler-pumps, we can illustrate only a 
few of those having special features. 


In Fig. 86 is shown a sectional view of the Knowles steam-pump. 
Freedom from stoppage on a dead centre of the valve-movement is 



Fig. 86.—Knowles single pump. 


secured by the use of the auxiliary piston A, which works in the steam- 
chest and drives the main slide-valve M. This main valve is of the 
B form and moves on a flat seat; it has on top a stem which fits into 
a recess in the piston A. The chest-piston A has a slight rotation 
from the curved rocker-bar R, which alternately covers and uncovers 



small ports, S, S, which enter the cylinder at each end near the head. 
The steam-piston runs over the main ports, and by its cushion operates 
the piston-valve and the main valve. 











































































































































THE INJECTOR AND THE STEAM-PUMP 


101 




The Knowles duplex pump is shown in section in Fig. 87. This 
pump has a double set of steam-ports which produce a cushion at 
each piston-stroke by covering 
the inside ports alternately; the 
plain D valve making the clos¬ 
ure by its movement. A rocker- 
arm linked to the piston-rod of 
each side of the pump operates 
the opposite valve. 

The Worthington duplex 

pump, Fig. 88, has the same 

valve-movement and cushion- 

, ■, .i i Fig. 88.— Worthington duplex pump, 

mg-ports as above described; 

but the water-piston is of the plunger form, with the inlet-valves at 
the bottom of the cylinder. 


Fig. 89 shows the vacuum-pump and jet-condenser, and Figs. 
90 and 91 show the details of the valve-gear used on the Deane single¬ 
cylinder steam-pumps. The main valve is operated by a small piston 

called the valve-piston. The 
ears on the main valve fit 
tightly in a slot cut in the 
valve-piston, so that when 
the valve-piston moves in 
either direction it carries the 
main valve with it. 

The valve-piston is fitted 
to and slides in a cylindrical 
bore in the valve-chest, and 
is actuated by steam ad¬ 
mitted to the opposite ends 
of the chest. The admission 
and exhaust of this steam 
are controlled by a second¬ 
ary valve, which admits or 
exhausts the steam for the valve-piston through the small ports at 
the sides of the cylinder and chest. The secondary valve derives its 
motion, through the valve-rod, tappets, and links shown, from the 


Fig. 89.- 


-Deane vacuum-pump with jet- 
condenser. 














































































102 


THE INJECTOR AND THE STEAM-PUMP 


main piston-rod. Thus, the movement of the secondary valve, and 
hence the valve-piston and main valve, are controlled by the main 



piston. The valve-piston, it will be noticed, has a steam-jacket which 
insures equal expansion of the parts and prevents binding. 

The piston-rod arm is fastened to the piston-rod, and through the 
connection of lever and links its motion causes the tappet-block to 
slide back and forth on the valve-rod between the two tappets. These 
tappets are keyed to the valve-rod so that when the tappet-block 
strikes either tappet it carries with it the valve-rod and secondary 
valve. When the piston moving in the direction indicated by the arrow 
has come almost to the end of the stroke, the tappet-block comes in 
contact with the left-hand tappet, and the further movement of the 
piston throws the secondary valve to the left until the edge A, Fig. 91, 



Fig. 91.—Valve-chest and auxiliary valve. 


uncovers the small port S. The port S, together with passages in 
the cylinder- and valve-chest, allows the steam to fill the space between 
the right-hand end of the valve-piston and the valve-chest head, 






















































































































THE INJECTOR AND THE STEAM-PUMP 


103 


and exerts a pressure forcing the valve-piston in the direction indicated 
by the arrow. In the illustration, Fig. 90, the valve-piston has already 
moved part of the way, carrying the main valve with it far enough to 
partially open the steam-port which admits steam to the right-hand 
end of the cylinder, and the main piston is ready to start back in the 
other direction. The port E and the chamber F in the secondary 
valve, as shown in Fig. 91, provide for the exhaust of steam from 
behind the left-hand end of the valve-piston in the same manner and 
at the same time that steam is admitted behind the right-hand end. 
The location of the exhaust-ports in the chest is such as to allow for 
proper cushioning of the valve-piston to prevent its striking the heads. 
The small ports on the 
other side of the steam- 
cylinder control the mo¬ 
tion of the valve in the 
other direction, and act in 
exactly the same manner. 

In case the steam-pressure 
should for any reason fail 
to start the valve-piston 
at the proper time there 
is a lug, B, Fig. 90, pro¬ 
vided on the valve-rod 
which comes in contact 
with the valve-piston and 
brings to bear the whole 
power of the steam-cylin¬ 
der to start it. It is readily seen that the correct timing of the 
valve-movements is independent of the position of the tappets. If 
they are too near together the valve will be thrown too soon, and 
thus the stroke of the pump will be shortened; while, on the other 
hand, if they are too far apart, the pump will complete its stroke 
without moving the valves. 

In the Cameron pump the plunger is reversed by means of two 
plain tappet-valves, shown in Fig. 92, and the entire mechanism thus 
consists of four pieces only, all working in direct line with the main 
piston. It is simple and without delicate parts. 

A is the steam-cylinder; C, the piston; L, the steam-chest; F, the 



K 


Fig. 92.—Sectional view of Cameron pump. 

































































































































104 


THE INJECTOR AND THE STEAM-PUMP 


chest-plunger, the right-hand end of which is shown in section; G, the 
slide-valve; H, a lever, by means of which the steam-chest plunger F 
may be reversed by hand when expedient; I, I are reversing-valves; 
K, K are the reversing-valve chamber-bonnets, and E, E are exhaust- 
ports leading from the ends of the steam-chest direct to the main 
exhaust by means of passages, M, M, which lead directly thereto, 
although the connection is not shown, being cut away in the sectional 
view, and closed by the reversing-valves I, I. 

The piston C is driven by steam admitted under the slide-valve G, 
which as it is shifted backward and forward alternately connects 
opposite ends of the cylinder A with the live-steam pipe and exhaust. 
This slide-valve G is shifted by the auxiliary plunger F; F is hollow 
at the ends, which are filled with steam, and this, issuing through a 
hole in each end, fills the spaces between it and the heads of the steam- 
chest in which it works. Pressure being equal at each end, this plunger 
F, under ordinary conditions, is balanced and motionless; but when the 
main piston C has travelled far enough to the left to strike and open 
the reversing-valve I, the steam exhausts through the port E from 
behind that end of the plunger F, which immediately shifts accordingly 
and carries with it the slide-valve G, thus reversing the pump. No 
matter how fast the piston may be travelling, it must instantly reverse 
on touching the valve I. In its movement the plunger F acts as a 
slide-valve to close the port E, and is cushioned on the confined steam 
between the ports and steam-chest cover. The reversing-valves I, I 
are closed, as soon as the piston C leaves them, by a constant pressure 
of steam behind them, direct from the steam-chest through the ports 
N, N, shown by the dotted lines. 

In the McGowan single-cylinder pump the main valve is of the B 
form and is driven by a chest-piston or valve-driver, as shown in Fig. 
93. Steam is alternately admitted through one of the cavities in the 
valve and is released through the other, the central port in the valve- 
seat admitting the live steam. Immediately below the ends of the 
steam-chest are two tappet-valves, which normally cover the auxiliary 
ports (shown by dotted lines), leading to the ends of the steam-chest 
and connecting the latter with the main exhaust-ports. The tappet- 
valves are raised by means of levers, the ends of which project 
downward and into the cylinder, so that when the piston nears 


105 


THE INJECTOR AND THE STEAM-PUMP 


the ends of the stroke it comes into contact with the levers and 
raises them slightly, the movement being merely sufficient to unseat 
the tappet-valves. 



The tappet-valve levers are pivoted on a pin in a recess near the 
main ports, the latter being indicated by dotted lines. 

When the piston reaches the end of the stroke, one of the tappet- 
levers is raised slightly and the corresponding valve is raised from its 
seat. This opens the port leading from the end of the steam-chest to 
the main exhaust-port 
and permits steam to 
escape into the latter. 

The pressure is thus les¬ 
sened on one end of the 
chest-piston or valve- 
driver, and the steam 
pressing on the opposite 
end forces the valve- 
driver to the opposite 
end of its stroke, thus 
reversing the distribu¬ 
tion of steam to the 
cylinder and starting the 
piston on the return 
stroke. The chest-piston 
is caused to move back 
and forth by live steam, 
the ends of the steam- 
chest being filled with 
steam at initial press¬ 
ure. Permitting steam to escape from one end of the steam-chest 
causes a difference of pressure on the two ends of the chest-piston, 
which difference represents the propelling force that moves the main 
valve. The tappet-valves have a very slight lift, so that they operate 
without shock or noise and with the minimum of wear. The main 
valve is connected with the chest-piston or valve-driver in such a 
manner that all lost motion and wear is taken up automatically. 

A short rocker-shaft, extending through the steam-chest and at 
right angles to the valve-travel, carries a toe which depends in a slot in 


Fig. 93.- 


-Sectional view of steam-end, McGowan 
pump. 






































































































































106 


T11E INJECTOR AND THE STEAM-PUMP 


the top of the chest-piston, so that in event the latter should chance 
to stop with the ports closed, the valve can be moved by hand without 
disconnecting any part of the pump. 

THE GUILD & GARRISON PUMP 

The steam-chest of this pump is a rectangular chamber, provided 
at each end with suitable cylinders to receive the pistons of the valve- 
driver E, Fig. 94. At the side of the valve-driver E, and in the 

steam-chest, is an auxil¬ 
iary slide-valve, G, Figs. 
94 and 95, which admits 
and releases the steam 
from the ends of the 
valve-driver. The valve- 
driver E has two slots 
at the centre, the lower 
one receiving the lug on 
the back of the main 
valve, and the upper one 
the toe on the rocker- 
shaft D. The rocker- 
shaft has two toes, the 
larger one engaging with 
the valve-driver, and the 
smaller one with the 
auxiliary slide-valve G, 
as shown in Fig. 96. 
Both the main and the 
auxiliary valves are plain slide-valves, so fitted as to take up wear 
automatically. The pendulum-lever J, Fig. 96, causes the shaft D to 
rotate, and by means of the toes previously referred to the valves are 
caused to move in unison. 

The auxiliary valve G is in every respect similar to the slide-valve 
of an engine, and admits and releases the steam to and from the ends 
of the valve-driver. 

The operation of the valves is as follows: The piston being at the 
end of the stroke, steam is admitted by the main valve, and the piston 



Fig. 94. —Steam-cylinder, Guild & Garrison pump. 






















































































THE INJECTOR AND THE STEAM-PUMP 


107 


moves toward the opposite end of the stroke. The two valves are 
also moved in the same direction by means of the rocker-shaft and the 
toes. This movement is con¬ 
tinued until the piston has 
nearly completed the stroke, 
when the auxiliary valve opens 
one of the small ports leading 
to the end of the valve-driver, 
thus admitting steam at one 
end and releasing it from the 
other, which causes the valve- 
driver to move from one end 
of the steam-chest to the other, 
which movement also shifts 
the position of the main valve and reverses the motion of the main 
piston. The valve-driver is moved the greater part of the distance by 

means of the toe on the 
rocker-shaft, the stroke 
or travel of the driver 
being completed, thus re¬ 
versing the steam-distri¬ 
bution by steam-press¬ 
ure, which brings the 
opposite end of the slot 
in the driver in position 
to be again engaged by the toe on the rocker-shaft for the return stroke. 

In the Blake single-cylinder pump the main valve, which controls 
the admission of steam 
to and the escape of 
steam from the main 
cylinder, is divided into 
two parts, one of which, 

G, Figs. 98 and 99, slides 
upon a seat on the main 
cylinder, and at the same 
time affords a seat for 
the other part, D, which slides upon the upper face of G. As shown 
in the illustrations, D is at the left-hand end of its stroke, and G at the 



Fig. 97.—Plan of Blake pump-valve. 




Fig. 95. —Sectional view of valve-chest, 
Guild & Garrison pump. 






































































































































































































108 


THE INJECTOR AND THE STEAM-PUMP 


opposite or right-hand end of its stroke. Steam from the steam- 
chest J is therefore entering the right-hand end of the main cylinder 
through the ports E and II, and the exhaust is escaping through the 
ports Hi, Ei, K, and M, which causes the main piston A to move from 
right to left. When the piston has nearly reached the left-hand end 

of the cylinder the valve- 



Fig. 98.—Section of Blake pump. 


motion moves the valve- 
rod P, and thus causes G, 
together with its supple¬ 
mental valves R and S, 
Si, Fig. 99 (which form, 
with G, one casting), to be 
moved from right to left. 
This causes steam to be 
admitted to the left-hand 
end of the supplemental 
cylinder, whereby the pis¬ 
ton B will be forced to¬ 
ward the right, carrying 


D with it to the opposite or right-hand end of its stroke; for the move¬ 
ment of S closes N, the steam-port leading to the right-hand end, and 
the movement of Si opens Ni, the steam-port leading to the opposite 
or left-hand end, at the same time the movement of Y opens the right- 
hand end of this cylinder to the exhaust, through the exhaust-ports 
X and Z. The parts G and D now have positions opposite to those 
shown in the cuts, and steam is therefore entering the main cylin¬ 
der through the ports Ei and 


Hi, and escaping through the 
ports H, E, K, and M, which 
will cause the main piston A 
to move in the opposite direc¬ 
tion, or from left to right, and 
operations similar to those al- 




v -- R 

Fig. 99.—Main valve and rider. 


ready described will follow when the piston approaches the right- 
hand end of the cylinder. By this simple arrangement the pump is 
rendered positive in action; that is, it will start and continue working 
the moment steam is admitted to the steam-chest. 

The main piston A cannot strike the heads of the cylinder, for 



























































































THE INJECTOR AND THE STEAM-PUMP 


109 


the main valve has lead; or, in other words, steam is always admitted 
in front of the piston just before it reaches either end of the cylinder, 
even though the supplemental piston B be tardy in its action and 
remain with I) at that end toward which the piston A is moving, 
for G would be moved far enough to open the steam-port leading to 
the main cylinder, since the possible travel of G is greater than that 
of D. 

The supplemental piston B cannot strike the heads of the smaller 
cylinder, for in its alternate passage beyond the exhaust-ports X 
and Xi it cushions on the 
vapor entrapped in the ends 
of the cylinder. 



Fig. 100.—Dean duplex pump. 


The Dean duplex pump, 

Fig. 100, varies but very little 
in its valve-gear from the 
Worthington and Knowles 
pumps of the duplex model, 
while its water-cylinder and valves are the same as the Knowles pat¬ 
tern. 

These sectional views represent the valve-gear and general action 
of a majority of the boiler feed-pumps on the market, and a further 
illustration may not be desirable. 

The basket-strainer, Fig. 101, is a most desirable appendage at 
or near the entering end of a suction-pipe drawing water from a river 

or pond, and consists of a perforated 
plate or frame covered with wire 
cloth, slid into a cylinder, as shown, 
with a cover and voke which allow of 
cleaning and of removal of fish and 
floating vegetation (eels often give 
much trouble in suction-pipes) with¬ 
out having to take up a submerged 
strainer. 

Pumps should go slow for their 
best work, especially when drawing 
from long suction-pipes; although a large air-chamber on the suction- 
pipe near the pump will help matters in regard to the pounding caused 




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Fig. 101.—Basket-strainer. 
























































































110 THE injector and the steam-pump 

by the piston by rapid motion in running away from the water- 
supply. 

In the pumping of hot water*this effect is so strong that at tem¬ 
peratures near to the boiling-point a pump will not lift the water; 
in such cases the pump should be set below the bottom of the hot- 
water tank. 

The air-chamber on the discharge side of a pump performs a 
most important service in equalizing the flow of water through long 
pipes and for preventing the noise and hammering in the pipe-lines 
by the elasticity of the air in the chamber which compensates for the 
intermittent action of the piston. 

The volume of the air-chamber varies in different makes of pumps 
from 2 to 3J times the volume of the water-cylinder in single-cylinder 
pumps, and from 1 to 2J times the volume of the water-cylinder in 
the duplex type. The volume of the water-cylinder is represented 
by the area of the water-piston multiplied by the length of stroke. 

For single-cylinder, boiler-feed pumps and those employed for 
elevator and similar service the volume of the air-chamber should be 
3 times the volume of the water-cylinder, and for duplex pumps not 
less than twice the volume of the water-cylinder. High-speed pumps, 
such as fire-pumps, should be provided with air-chambers containing 
from 5 to 6 times the volume of the water-cylinder. 

The diameter of the neck should not exceed one-third the diameter 
of the chamber. When the pumps work under pressure exceeding 
85 or 90 pounds per square inch, it is frequently found that the air 
gradually disappears from the air-chamber, the air passing off with 
the water by absorption. In this case air should be supplied to the 
air-chamber unless the pump runs at very low speeds, say, from 10 to 
20 strokes for the smaller sizes and from 3 to 5 strokes per minute 
for pumping-engines. At higher speed and with no air in the air- 
chamber the valves are apt to seat heavily and cause more or less jar 
and noise, and the flow of water will not be uniform. In large pumping- 
plants small air-pumps are employed for keeping the air-chambers 
properly charged. In smaller plants an ordinary bicycle-pump and 
a piece of rubber tubing are used to good advantage. The water- 
level in the air-chamber should be kept down to from one-fourth to 
one-third the height of the air-chamber for smooth running at medium 
and high speeds. 


CHAPTER 


VIII 


INCRUSTATION IN BOILERS, AND ITS REMEDY 

Apart from the frequent blowing off of boilers for discharging the 
floating material that otherwise would settle upon the tubes or plates 
and form incrusting scale, there are ingredients needed to so change 
the chemical combination of the scale-forming matter that it may be 
made soluble at the boiler temperature and blown out or changed into 
solid particles that do not crystallize on the surface of tubes and plates, 
and that can be partially blown out or cleaned out at stated periods. 

A knowledge of the nature of the scale-forming material in water 
that is to be used for steam-making is essential, and if this cannot be 
readily obtained from tests, a sample of the scale may give a clew to 
its chemical composition. The principal compounds found in such 
material are carbonate of lime, sulphate of lime, carbonate of magnesia, 
and sulphate of magnesia; any of which may be nearly pure, or com¬ 
bined or mixed with clay, fine sand, or mud, which tends to modify 
the hardness of the scale or settles in the boiler as a sludge. The 
scale from water containing carbonate of lime alone is not as hard as 
the scale from the sulphate, and is detached much easier. The sul¬ 
phate scale may be recognized by its sulphurous fumes when heated. 

The base of many boiler-compounds made for feeding to boilers 
with the water is carbonate of soda. Caustic soda and sodium 
tannate, or extract of oak, sumac, and hemlock bark—mixed with sal 
soda, sal ammoniac, and triphosphate of sodium—are also used. For 
the sulphate-of-lime water caustic soda gives a strong reaction, in 
which sulphate of soda is formed—which is soluble—and hydrate of 
lime falls as a powder. 

PURIFICATION OF BOILER FEED -WATER 

In large steam-plants the purification of the water before feeding 
it to the boilers is most desirable in the line of economy and dura¬ 
bility. For this purpose a water-purifying apparatus is in order, and 

ill 


112 


INCRUSTATION IN BOILERS, AND ITS REMEDY 


we illustrate in Fig. 102 an automatic one in use by the Chicago & 
Northwestern Railway Co. for purging the water for their locomo¬ 
tive service. The following taJL>le of the causes of incrustation and 
corrosion, with their effect and remedies has been formulated to meet 
these troubles with approved treatment: 


Table XVII. —Causes of Incrustation, Corrosion, and their Remedies. 


Cause of trouble. 

Incrustation. 

Treatment of water. 

Carbonate of lime. 

Soft scale. 

Slaked lime, sal-soda. 

u u a 

Sal-soda, caustic soda. 

Slaked lime and sal-soda. 
Sal-soda, or caustic soda. 

j- Alum, and filter. 

Slaked lime, sal-soda, or caustic 
soda. 

Frequent blowing off from boiler, 
or neutralize with hydrochloric 
acid. 

Slaked lime, sal-soda. 

“ of magnesia. 

Sulphate of lime. 

u 

Hard scale.... 

i l 

Corrosion. 

Precipitation, 
or soft scale. 
Foaming and 
corrosion. . .. 

Foaming ... . j 

Corrosion. 

“ of magnesia. 

Chloride of magnesia. 

Sediment of sand, clay, and mud j 
Organic matter.j 

Alkaline water. 

Acid w aters. 


Triphosphate of sodium may be also used instead of lime, but is 
somewhat more expensive than the lime treatment. 

In the use of a purifying apparatus it is necessary to find by trial 
how much of the chemicals is required in a saturated mixture with 
water, which should be stored in a tank from which the proper 
quantity may be automatically drawn and mixed with the water- 
supply and allowed to settle in large tanks. 

In Fig. 102 is shown a cross-section of the apparatus, which con¬ 
sists of a receiving-tank for the chemicals, a, with a filter-screen at b, 
from which the chemicals are drawn into a stirring-tank to keep the 
mixture uniform, whence they are forced to flow to and mix with the 
boiler-feed water at a uniform rate by measurement in a tilting-tank. 
By opening the valve e this solution is allowed to run into the chemical 
tank d. To thoroughly mix and keep the solution stirred up in the 
chemical tank d, stirring-blades are fixed on the vertical shaft g, 
which rotates in the centre of this tank. In order to measure and 
deliver predetermined quantities of the chemical solution, the chem¬ 
ical tank d is provided with two pumps, k and k 1 , Fig. 103, connected 
at the lower portions to the chemical tank d through the T’s l and l 1 . 





















113 


INCRUSTATION IN BOILERS, AND ITS REMEDY 

The upper portions of these pumps have discharge-pipes, m and m 1 , 
which discharge into a funnel, n, attached to an elbow terminating 
on the hard-water supply-pipe, so that just before the hard water 
passes out ol this pipe the chemical solution is mixed with it. 

To obtain the best results it is essential that the quantity of the 
standard chemical solution and hard water be mixed in proper 
proportions, and also that this be done regularly whenever the ap¬ 
paratus is being used; also that it be done economically. To do 



Fig. 102.—Cross-sections of purifying apparatus. 


this a tilting-vessel, p, Fig. 103, is used. It is supported on a shaft, q, 
which is located directly under the elbow from which the mixed hard 
water and chemical solution are discharged. 

This tilting- and measuring-vessel is divided into two compart¬ 
ments of equal capacity, p 1 and p 2 . When it is in the position shown 
in Fig. 103, the mixture of hard water and chemicals falls from the 
discharge-elbow o into the compartment p 1 . When this compart¬ 
ment is nearly filled it counterbalances the weight of the other com¬ 
partment, p 2 , so that the vessel tilts until it strikes the spring 30, 
emptying the contents of the compartment p 1 , and at the same time 
bringing the other compartment, p 2 , under the discharge-elbow o. 
When this in turn is filled it reverses the movement of the tilting- 
vessel p, emptying the contents of the compartment p 2 , and bringing 
the compartment p l again under the elbow o. For convenience these 
compartments, p 1 and p 2 , are made of such size that 100 gallons of 









































































































































114 


INCRUSTATION IN BOILERS, AND ITS REMEDY 


water are required to fill them to the point where they commence to 
tilt and empty their contents. 

Having determined the amouftt of a standard solution of chemicals 
required to precipitate the scale-forming compounds from, say, 100 
gallons of any hard water, it is necessary to mix it with the 100 
gallons of hard water .in one of the compartments p l or p 2 . This is 



done by regulating the length of the stroke of the pumps k and k l , 
which pump the standard chemical solution from the tank d into the 
funnel n. These pumps, k and k 1 , are operated by the til ting-vessel 
p in the following manner: 

The plungers u are connected to a walking-beam, v, which is rotably 
mounted on the shaft w. The ends of this walking-beam are con¬ 
nected, by means of the chains x and x 1 , with studs, x 2 , on each end of 
the tilting-vessel. If the parts are in the position shown in Fig. 103, 
when the tilting-vessel p is tilted downwardly to the left the plunger 
of the pump k is raised so that a quantity of the standard chemical 
solution is delivered into the funnel n, and flows with the hard water 
into the compartment p 2 . When 100 gallons are in it, the tilting- 
vessel p operates in the opposite direction, causing the other pump, 
k 1 , to operate, and delivers a quantity of the standard chemical solu¬ 
tion into the funnel n, whence it flows with the hard water into 
the compartment p l . It will be understood that the hard water is 
running constantly through the elbow o, and that the two pumps k 
and k l are intermittent in their action. The quantity of the standard 











































































































































115 


INCRUSTATION IN BOILERS, AND ITS REMEDY 

chemical solution delivered at each stroke of these pumps is regulated 
by the length of the strokes. This can be adjusted by the length of 
the chains x and x 1 , so that a predetermined quantity of chemical 
solution will be delivered at each stroke. From this description it 
will readily be seen that a fixed quantity of chemical solution is dis¬ 
charged into the elbow o and flows with the hard water into each 
compartment of the tilting-vessel p, in proportion to the amount of 
hard water that is required to cause this vessel to tilt. 

It is desirable to automatically and economically operate the 
vertical shaft g in the chemical tank d, so that the horizontal blades 
attached to it will keep the chemical mixture thoroughly agitated. 
To do this it is geared to the horizontal shaft w by the pinions y and y l . 
The other end of the horizontal shaft w is provided with a sprocket- 
wheel, y 2 , around which a link-belt chain passes, the ends of this chain 
being attached to the ends of the tilting-vessel by the studs y A . It 



Fig. 104.—Pump-house and settling-tanks. 


will readily be seen by this arrangement that whenever the tilting- 
vessel p moves, the stirring-blades attached to the vertical shaft g 
in the chemical tanks also move, thus agitating the chemical mixture 
in the tank d. 

For convenience in measuring the height in the tank of this 
chemical mixture, a pipe, z, Fig. 103, is attached to the side of the tank 
d near its bottom. In this pipe is a float, z 1 , attached to a graduated 
scale, z 2 , from which can be read the quantity of liquid in the tank d. 


























































































116 


INCRUSTATION IN BOILERS, AND ITS REMEDY 


The above-described apparatus automatically mixes the proper 
quantity of the chemical solqjtion with each 100 gallons of hard 
water delivered by the steam-pump, and utilizes the weight of the 
water to furnish power to operate it. The result of this mixture is 
that the scale-forming matter that was in solution in the hard water 
is thrown out of solution, but remains in suspension in the treated 
water. This is separated from the treated water in the following 
manner: 

By referring to Fig. 104 it will be seen that the apparatus is located 
in the second story of the pump-house, and that the pump-house is 
located between two tanks placed on the ground. The tilting-vessel 
above described empties its contents into a wooden box which is 
provided with troughs leading to the two settling-tanks. These 
troughs are provided with shut-off gates, so that the water can be run 
into whichever tank is desired. It will be seen that the troughs 
empty their contents into vertical pipes that extend to the bottom 
of the tanks and terminate in elbows, so as not to disturb the clear 
water drawn from the top. 

The water for boiler use is drawn from the float-nozles at the 
surface of the water, which swing downward as the water-level is 
drawn down. The tanks are cleaned alternately. 

From records of many trials of the effect of incrustation on fuel- 
consumption in Europe and the United States, it has been found that 
there is an average loss of 15 per cent, in full by yy-inch scale, and 
a greater loss as the scale thickens. 

THE FACTOR OF EVAPORATION 

To determine the efficiency of a boiler, or the amount of water 
evaporated by a pound of fuel, it is necessary to reduce the amount 
of evaporation which actually takes place from the temperature of 
the feed-water at the temperature of the steam, to an equivalent 
amount at and from 212° F. The factor of evaporation at 212° F„ 
and atmospheric pressure =1.00. 

Then from the total heat-units in Column 6 of Table XX of the 
properties of saturated steam for any absolute pressure, subtract 
the heat-units in the feed-water from 32° F. to its temperature; divide 
the remainder by the constant 966.1 (the latent heat of steam at 212° 


XVIII. —Factors of 


INCRUSTATION IN BOILERS, AND ITS REMEDY 117 


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118 


INCRUSTATION IN BOILERS, AND ITS REMEDY 


F.), and the quotient will give the factor of evaporation as per Table 
XVIII. For example: the factor of evaporation for 100 pounds abso¬ 
lute pressure—85.3 gauge-pressure—from water at 212° F. and feed- 

water at 100° F., will be ^^^—-^=1.153, as in the table, Column 

966.1 

100, and opposite 100° F. in the first column. 

The total heat-units from the feed-water temperature in the 
steam, at any given pressure, may be readily obtained by multiplying 
the total heat-units at 212° F. as a constant (966.1), by the factor of 
evaporation for the feed-water temperature in the first column at 
the intersection of its line in the columns of absolute pressure, Table 
XVIII. 

Intermediate temperatures and pressures may be obtained by 
interpolation. The use of the factor of evaporation is apparent as a 
ready method for obtaining the actual number of pounds of water 
evaporated in a boiler from and at a temperature of 212° F. per 
pound of coal or of combustible, if the combustible value of the coal 
is known. 

For example: with feed-water at 100° F., average steam-pressure 
during trial 75.3 gauge = 90 pounds absolute, with say 40 pounds coal 
burned for any unit of time and 340 pounds of water fed to the boiler for 
the same unit of time; then W°- = 8.5 pounds of water evaporated at 
100° F. per pound of coal. Then for the evaporation from and at 
212° F., the factor of evaporation for 100° and 90 pounds is by the 
table 1.151, and 8.5x1.151=9.27 pounds water evaporated at 
212° F. 


THE JET-CONDENSER 

Where a sufficient quantity of water suitable for boiler-feeding 
purposes is available, the jet-condenser, being the simplest and easiest 
to operate, is preferable. Where, however, water suitable for boiler¬ 
feeding is not available, a surface-condenser may be used. In this 
type the steam is condensed in a condensing-chamber on the surface 
of tubes through which cold water is circulating, and the distilled 
water so furnished may be again fed to the boilers. Where any con¬ 
siderable amount of cylinder-oil is used, some provision must be 
made with surface-condensers to remove this oil before the water is 
fed to the boilers. With either type the quantity of water to be 



119 


INCRUSTATION IN BOILERS, AND ITS REMEDY 

circulated through the condenser should be from twenty to forty 
times the quantity of steam to be condensed, depending upon the 
temperature of the water available for condensing purposes. 

Condenser manufacturers have recently introduced several types 
of self-cooling condensers by which the hot water delivered from the 
condenser-pumps can be cooled and reused, so that with water suffi¬ 
cient in quantity for boiler-feed purposes only, the plant may be 
located at any convenient point and still retain the fuel-saving and 
other benefits of high steam-pressures and con¬ 
densers. 

The condenser-head, shown in section in Fig. 

105, consists of a suitable steam-chamber, usually 
in the form of a large return-bend. This is fitted 
with a relief-valve at the top which closes auto¬ 
matically, due to its own weight aided by a light 
spring. When a vacuum exists in the condenser- 
head, the valve is pressed more firmly against its 
seat by atmospheric pressure of about 15 pounds 
per square inch. 

Connected with one of the openings in the 
steam-chamber, or return-bend, is the regulating- 
nozle, which is movable vertically and is raised by 
means of a threaded stem and hand-wheel. The 
nozle regulates the width of the inlet-orifice for the condensing water 
according to the load, the water entering the side of the nozle-chamber 
and surrounding the nozle, flows in a thin sheet or film through the 
annular orifice formed between the nozle and its seat. 

Below the chamber is connected the throat or combining-tube, 
the bore of which gradually contracts toward the middle of its length 
and then enlarges toward the lower end, where it is connected to 
the tail-pipe, which extends to 34 feet below the nozle and dips into 
the hot-well for the purpose of a water-seal to prevent air entering 
the pipe and to resist the atmospheric pressure from without. There¬ 
fore, if the tail-pipe were less than 34 feet long, measured between 
the points mentioned, water supplied to the condenser would not 
leave the latter without the use of a pump. But with a fall of 34 
feet, a given quantity of water admitted around the hollow cone, or 
nozle, causes the discharge of a corresponding amount into the hot- 



TT 


Fig. 105.—Siphon 
condenser. 


















120 INCRUSTATION IN BOILERS, AND ITS REMEDY 

well, so that the level in the condenser never can rise to the water- 
inlet. + 

Water passing through the annular orifice formed by the hollow 
cone flows downward in a cone-shaped film into the contracted throat, 
where its velocity is sufficiently increased to enable it to carry air 
along with it, thus producing a vacuum in the exhaust-pipe. Steam 



Fig. 106.—Siphon condenser connected. 


flows downward through the regulating-nozle and into the cone-shape 
film of water, where it is condensed. The continuous condensation 
of steam and the ability to get rid of the water may sometimes cease, 
when the exhaust-valve will be raised, allowing the steam to escape 
into the atmosphere. If it becomes necessary to break the vacuum, 
the relief-valve can be opened from the engine-room floor by means 
of chains connected with a lever attached to the valve. There are a 






























































































































INCRUSTATION IN BOILERS, AND ITS REMEDY 


121 


number of this type of condensers, of various models, on the market, 
all involving the same principles as here shown. 

The ejector-condenser, Fig. 107, is of the Korting type, with a 
three-way valve by which the exhaust-steam is passed to the atmos¬ 
phere or is condensed by the multiple-nozle water-jet. The high 
velocity of the water-jet past the angular orifices in the nozle main¬ 
tains the required vacuum without recourse to a pump or long vertical 
pipe. 

A sectional view of a Worthington direct-acting jet-condenser is 
given in Fig. 108. In all essential features it is a duplex, direct-acting 



Fig. 107.—Ejector-condenser. 



Fig. 108.—Jet-condenser pump. 


pump with a condensing-chamber or cone connected with the pump- 
suction or suction-chamber. The exhaust-pipe from the .engine is 
connected at A, and the pipe supplying the injection-watei is con¬ 
nected at B, which point on the condenser should never be more than 
18 feet above the surface of the water from which the supply of con¬ 
densing water is to be drawn. The discharge from the condenser 
flows out at J through a pipe leading to the hot-well. 

When the pump is started, a partial vacuum is created in the 
suction-chamber above the valves H, II, in the cone F, in the exhaust- 
pipe at A, and in the injection-pipe connected at B. As soon as suffi¬ 
cient air has been exhausted, water begins to flow through the pipe C 











































































122 


INCRUSTATION IN BOILERS, AND ITS REMEDY 


and the spray-nozle D. Continued motion of the pump increases 
the vacuum up to the working*point, 26 or 27 inches. Water issuing 
from the nozle D is broken into a fine spray which completely fills 
the condensing-chamber or cone beneath it, so that upon starting 
the engine the exhaust-steam is compelled to flow into the spray of 
cold water. 

The mixture of condensed steam and injection flows downward 
through the tapered throat F into the suction-chamber of the pump 
with sufficient velocity to carry with it any air that may have leaked 
into the exhaust-pipe, together with the air brought in with the injec¬ 
tion-water. The direction of the water in the pump may be easily 
traced, the pump discharging both water and air through the dis¬ 
charge-valves I, I and outlet J. 

Many manufacturers of pumps are now making the condenser 
attachments to their vacuum-pumps. 

WATER REQUIRED FOR CONDENSING THE 

EXHAUST 

Evidently the heat given up by the steam must equal the heat 
gained by the cooling water, and for each pound of steam condensed 
there will be a certain number of pounds of cooling water used under 
a given set of conditions. This makes it possible to determine the 
theoretical ratio between the weight of condensed steam and the 
weight of cooling water used, and this theoretical ratio will for the 
jet-condenser correspond to the actual ratio. For the surface-con¬ 
denser the amount of cooling water used will be about 20 per cent, 
in excess of the theoretical value. 

The heat removed from a pound of steam, with variable terminal 
pressure, is but slight within practical limits. For instance, at 30 
pounds absolute terminal pressure, the heat contained is 1,190.3 
thermal units, while at 5 pounds absolute pressure it is 1,163.5 thermal 
units, a difference of a little over 2 per cent.; hence, it is not necessary 
to figure on small differences in terminal pressure. Table XIX shows 
the ratio of the cooling water to the condensed steam, or, in other 
words, the number of pounds of cooling water needed per pound of 
steam for the terminal pressure of 15 pounds absolute, and for final 
temperatures of the condensed steam from 90° to 134° F. 


INCRUSTATION IN BOILERS, AND ITS REMEDY 123 

Table XIX.—Pounds of Water Required to Condense 1 Pound of Steam 
at Exhaust-Pressure of 15 Pounds Absolute, in Jet -Condensers. 


Temperature 

air-pump 

discharge. 






Entering Temperature of 

Injection-W ater. 






35 

40 

45 

50 

55 

60 

65 

70 

75 

80 

85 

90 

Pounds of condensing water required per pound of steam. 

90 

20. 

0 

22. 

0 

24. 

4 

27. 

5 

31. 

4 

36. 

7 

44. 

0 

55. 

0 

73. 

3 

110. 

0 

220. 

0 



92 

19. 

2 

21. 

1 

23. 

4 

26. 

1 

29. 

7 

34. 

3 

40. 

7 

49. 

9 

64. 

6 

91. 

5 

156. 

8 

549. 

0 

94 

18. 

6 

20. 

3 

22. 

4 

24. 

9 

28. 

1 

32. 

2 

37. 

8 

45. 

7 

57 

7 

78. 

1 

121. 

8 

274. 

0 

96 

17. 

9 

19. 

5 

21. 

4 

23. 

6 

26. 

7 

30. 

4 

35. 

3 

42. 

1 

52. 

1 

68. 

4 

99. 

4 

182. 

3 

98 

17. 

3 

18. 

8 

20. 

6 

22. 

7 

25. 

4 

28. 

7 

33. 

1 

39 

0 

47 

5 

60 

7 

84 

0 

136. 

5 

100 

16. 

8 

18. 

2 

19. 

8 

21. 

1 

24. 

2 

27. 

2 

31 

1 

36 

3 

43 

6 

54 

5 

72 

7 

109 

0 

102 

16 

2 

17 

5 

19 

1 

20 

9 

23. 

1 

25 

9 

29 

4 

34 

0 

40 

3 

49 

5 

64 

0 

90 

7 

104 

15 

7 

17 

0 

18 

4 

20 

1 

22 

2 

24 

7 

27 

8 

31 

9 

37 

4 

45 

2 

57 

2 

77 

6 

106 

15 

3 

16 

4 

17 

8 

19 

4 

21 

3 

23 

6 

26 

4 

30 

1 

35 

0 

41 

7 

51 

6 

67 

7 

108 

14 

8 

15 

9 

17 

2 

18 

7 

20 

4 

22 

5 

25 

2 

28 

5 

32 

8 

38 

6 

47 

0 

60 

1 

110 

14 

4 

15 

4 

16 

6 

18 

0 

19 

6 

21 

6 

24 

0 

27 

0 

30 

9 

36 

0 

43 

2 

54 

0 

112 

14 

0 

15 

0 

16 

1 

17 

4 

18 

9 

20 

7 

22 

9 

25 

7 

29 

1 

33 

6 

39 

9 

49 

0 

114 

13 

6 

14 

5 

15 

.6 

16 

8 

18 

2 

19 

9 

22 

0 

24 

5 

27 

6 

31 

6 

37 

1 

44 

8 

116 

13 

.3 

14 

1 

15 

.1 

16 

.3 

17 

6 

19 

2 

21 

1 

23 

3 

26 

2 

29 

8 

34 

6 

41 

3 

118 

12 

.9 

13 

.7 

14 

.7 

15 

.8 

17 

.0 

18 

5 

20 

.2 

22 

.3 

24 

9 

28 

.2 

32 

.5 

38 

3 

120 

12 

.6 

13 

.4 

14 

.3 

15 

.3 

16 

.5 

17 

.8 

19 

.5 

21 

.4 

23 

.8 

26 

.7 

30 

.6 

35 

7 

122 

12 

.3 

13 

.0 

13 

.9 

14 

.8 

15 

.9 

17 

.2 

18 

.7 

20 

.5 

22 

.7 

25 

4 

28 

.9 

33 

.4 

124 

12 

.0 

12 

.7 

13 

.5 

14 

.4 

15 

A 

16 

.7 

18 

.1 

19 

.7 

21 

.8 

24 

.2 

27 

.3 

31 

.4 

126 

11 

.7 

12 

.4 

13 

.1 

14 

.0 

15 

.0 

16 

.1 

17 

.4 

19 

.0 

20 

.9 

23 

.1 

26 

.0 

29 

.6 

128 

11 

.4 

12 

.1 

12 

.8 

13 

.6 

14 

.5 

15 

.6 

16 

.9 

18 

.3 

20 

.0 

22 

.1 

24 

.7 

27 

.9 

130 

11 

.2 

11 

.8 

12 

.5 

13 

.2 

14 

.1 

15 

.1 

16 

.3 

17 

.7 

19 

.3 

21 

.2 

23 

. 6 

26 

.5 

132 

10 

.9 

11 

.5 

12 

.2 

12 

.9 

13 

.7 

14 

.7 

15 

.7 

17 

.1 

18 

.6 

20 

.3 

22 

.5 

25 

.2 

134 

10 

.7 

11 

.2 

11 

.9 

12 

.6 

13 

.4 

14 

.3 

15 

.3 

16 

.5 

17 

.9 

19 

.6 

21 

.6 

24 

.0 


This table has been computed from the formula Q = _E___—, in 

which Q = quantity of water in pounds to condense 1 pound of steam, 
or 25.85 cubic feet at exhaust temperature of 213.1° F.; T = tempera¬ 
ture of water discharged from the condenser; t = the difference in 
temperature between the injection- and the discharge-water, and 
1,190 = the total heat of the steam, plus the loss from radiation in the 
operation of the condenser. 

The surface-condenser, so useful in the line of economy where 
the cost of water claims a saving of its waste in the jet-condenser, 
comes to the front in connection with the cooling-tower as an econo¬ 
mizer in the generation of steam-power. There are a number of 
models in design with claims of efficiency. 

In Fig. 109 is shown a two-section condenser with a cast-iron shell 
and brass tubes. The difference in expansion between the brass 












































124 


INCRUSTATION IN BOILERS, AND ITS REMEDY 


tubes and the cast-iron shell is provided for by stuffing-boxes and 
glands at one or both ends. r Mie cooling water enters through the 



lower tier and discharges through the upper one for the best efficiency 
of the condenser, with the steam passing in the opposite direction. 

A three-section surface-condenser and heater is shown in Fig. 
110. The upper section is divided in two parts as a feed-water heater, 
through which part of the water used for condensing is passed through 



Fig. 110.— Combination condenser. 


one part of the upper section and returned by the other side-chamber. 
By this arrangement the feed-water is heated to as high a tempera¬ 
ture as practicable by first contact with the exhaust-steam. 

The double-tube type, Fig. Ill, is one in which the shell encloses 
both tube-heads at one end, in one of which the central tubes are 
carried through the inner compartment, and both inner and outer 
concentric tubes are expanded in their respective heads. 

The outside tubes are capped or welded close at their farther 
ends. The circulation is made complete by its discharge from the inner 













































































































INCRUSTATION IN BOILERS, AND ITS REMEDY 125 

to the outer tube, which is the condensing-surface; thus all troubles 
from expansion are avoided. 

A novel system of surface-condensation is shown in Fig. 112, in 
which a cylinder is filled with small brass tubes, open for receiving a 
sprav-jet of water at one 
end; a cone and suction- 
blower are at the other 
end, as well as the usual 
vacuum-pump. In its ac¬ 
tion a spray-jet of water is 
thrown against the tubes at 
one end, and with a large 
volume of air is drawn 
through the tubes by a 
suction-blower at the end 
of the conical chamber. 

The water is vaporized, and with the air takes up the heat of the 
exhaust-steam, which is discharged in a vapor by the blower. The 
economical claim for this arrangement is that but 1 pound of water is 
used for condensing 1 pound of steam. 



Fig. 112.—Spray surface-condenser. 


The large number of oil-extracting devices on the market, of various 
models, need no discussion as to their merits, as each has a claim to 
be the best. They are a great need and in general use, and are usually 
connected in the exhaust-pipe near the surface-condenser. The leading 
principle of action of these separators is their sudden deflection of 
the passing steam by an apron, which may be curved or flat, pierced 
with slots, holes, or with corrugated surfaces, arranged to catch the 
oil and-drain it to a receptacle below. 


STEAM INLET 






1 


Fig. 111.—Concentric tube-condenser. 





























































































126 INCRUSTATION IN BOILERS, AND ITS REMEDY 

In Fig. 113 is shown a vertical and a horizontal pattern of the 
Austin Separator Co., and in Fig. 114 a separator of the Lippincott 
pattern, with a broad spherical apron at A and catch-plates at B, C, D, 
the steam being deflected around the outside of the spherical plate A. 



Fig. 113.—Oil-separators. 



Fig. 114.—Lippincott separator. 


A combined vacuum air-pump and water-circulating pump for 
large condensing-engines is shown in Fig. 115. It is of. the Conover 
type of the Watson Machine Co. Its compact design makes it a good 
study for the student and engineer. It is operated by a pair of 



Fig. 115.—Air-and circulating-pump. 


frame just below the beam. This 
is made for engines of from 5,000 


compound Corliss cylinders, with 
dash-pots complete. The beam- 
ends connect with the steam- 
cylinders, and at mid-distance 
to its centre are connected to the 
pumps, and from one of these to 
the crank, the shaft of which is 
seen in the centre of the illustra¬ 
tion. The shaft carries a fly¬ 
wheel at the rear end and drives 
the governor. The air-pump is 
single-acting; the circulating- 
pump is a double-acting trunk 
pattern, located at the right. 
The receiver is attached to the 
type of air- and circulating-pumps 
to 20,000 horse-power. 



































































































































































































INCRUSTATION IN BOILERS, AND ITS REMEDY 


127 


A novel air-pump for medium-sized condensing-engines is the 
Edwards type, E ig. 116, which has no suction-valves. Ports around 
the cylinder are opened by passing the piston past them to the bottom 
of the cylinder. 

The water and air enter above the piston and are discharged 
through valves above, which are water-sealed; the discharged water 
flowing over a dam, as shown by the arrow. A 
water-filled cup seals the piston-rod below the 
stuffing-box gland. The descent of the piston 
forms a vacuum above it, which is a powerful 
draught at the moment of opening of the cylin¬ 
der-ports by the piston. 


WATER-COOLING TOWERS 

The saving of water in locations where it is 
deficient for the necessities of steam-power is a 
matter of great importance, as in arid regions, and 
of economy, where its cost is of material amount. 

The main feature of the cooling-tower is derived 
from the intimate contact of cool air, circulated by 
a fan driven by any convenient power, or by the 
natural draught caused by the heating of the air 
by contact of the falling spray or sheets of hot 
water. In this manner the hot water from a jet- or 
surface-condenser may be cooled sufficiently for 
use again in the condenser. 

The cooling-towers are filled in a variety of 
material and forms, such as hanging curtains of 
galvanized-iron netting, or strips of thin wood and 
tile in tiers crossing each other, so arranged as to 
give the greatest wet surface and also the greatest 
area of airway. 

In Fig. 117 we illustrate by a section the 
Worthington water-cooling tower, which consists 
of a cylindrical steel shell open at the top, sup¬ 
ported upon a suitable foundation, and having fitted at one side 
a fan, the function of which is to circulate a current of air through 



Fig. 117. —Air-cool¬ 
ing tower. 



Fig. 116.—Edwards’s 
air-pump. 









































































































































128 INCRUSTATION IN BOILERS, AND ITS REMEDY 

the tower and filling This filling consists of layers of cylindrical 
tubular tiling, which rest upon a grating supported by a brick wall 
extending around the circumference of the tower. The heated dis¬ 
charge-water from the condenser enters the tower at the side, passes 
up the central pipe, and is delivered on the upper layer of tiling and 
over the whole cross-section of the tower by a distributing device con- 



Fig. 118.—High-vacuum installation with cooling-tower. 


sisting of four pipes, which are caused to rotate about the central 
water-pipe by the simple reaction of the jets of heated water issuing 
from one side of each pipe. The water thus delivered spreads over 
the outside and inside surfaces of the walls of the tiling and forms a 
continuous sheet, which is presented to the action of the air. 

In Fig. 118 is represented a complete power-plant of the Worth¬ 
ington model with a'jet or barometric condenser, natural draught- 
cooling tower, combined hot- and cold-water pump, and a vacuum- 
pump. 













































































































































































































































INCRUSTATION IN BOILERS, AND ITS REMEDY 


129 


It will be seen on inspection that the exhaust from one or a series 
of engines passes into a trunk-pipe from which a rising pipe leads to 
the head of the ejector-condenser and on to a relief-valve. The cold- 
water cylinder of the circulating-pump takes its suction from the cold- 
water well in the tower and discharges into the head of the jet-con¬ 
denser. The hot-water cylinder of the same pump takes its suction 
from the hot-well of the condenser and discharges at the top of the 
tower in fine streams that trickle over the surface of the tiling in 
contact with the up-flowing air. In order, however, to obtain the 
highest vacuum without using an abnormal amount of water to carry 
off the air, a separate dry-vacuum pump is used, as shown in the 
illustration. The air that is not carried off by the water is taken 
from the space under the spray-cone in the condenser. By this means 
it is possible to get as much as 29 inches of vacuum under the most 
favorable conditions. 

The loss of water is minimized in this arrangement to the amount 
vaporized to the air in the cooling-tower and the leakages. 


♦ 


CHAPTER IX 

STEAM ABOVE ATMOSPHERIC PRESSURE 

Steam under pressure and confined, as in a boiler, has a potential 
energy due to its pressure, which becomes kinetic, a moving force, 
when following the piston of an engine from the boiler-pressure or by 
its force of expansion. 

Steam, like fluids under pressure, becomes a force by momentum 
from its pressure and expansive velocity when impinging on the 
blades of the steam-turbine. 

Tire derivation of its energy, both potential and kinetic, is from 
heat in its specific and latent forms, which, combined with water, 
gives it the elastic properties produced in its vapor. 

Heat is the basis of energy in nature, in life, and in work of the 
most important value to our industries; it has a measured value, 

the heat-unit or British thermal unit, equivalent to the amount 

* 

received to raise 1 pound of water at the temperature of its greatest 
density, 39° F., through 1 degree of the Fahrenheit scale. 

DIAGRAM OF STEAM-GENERATION 

The rise in temperature of water in its frozen state from absolute 
zero, its absorption of heat in thermal units, its further absorption of 
heat in melting and rise of temperature to its boiling-point, and its 
conversion into steam, are graphically shown in the diagram (Fig. 119) 
in which the vertical scale represents the temperature from absolute 
zero, and the horizontal scale the heat-units absorbed during the 
change from ice to steam. 

The divergent lines at the right show the thermal-heat difference 
of steam at constant volume (C v ) and constant pressure (C p ). All the 
inclined lines should be slightly curved to show the change in specific 

heat, but it is not readily shown on so small a diagram. 

130 


STEAM ABOVE ATMOSPHERIC PRESSURE 


131 


Steam is treated in its work under different conditions, essential 
to its economical use: 

1. As saturated steam; its condition when generated in quiet 
contact with its water of generation. 

2. As wet steam; its condition when by the violent action of 
its generation from an overworked or foaming boiler it is loaded 
with minute vesicles of 

water containing no latent 
heat and consequently non- 
expansive in its working 
economy; although its spe¬ 
cific heat at high press¬ 
ures and temperatures 
may evolve a minute por¬ 
tion of the water-vesicle 
into vapor during expan¬ 
sive work. 

3. As dry steam; its con¬ 
dition when it contains no 
vesicular moisture; it may 
be saturated steam or with 
initial or expansive super¬ 
heat. 

4. As superheated 
steam, which is at a tem¬ 
perature above that of the 
water from which it is 



QUANTITY OF HEAT IN BRITISH THERMAL UNITS 

generated, either by some Fig- 119 ._ Diagram of stea m-generation. 
peculiar boiler construc¬ 
tion, or at a temperature largely increased by passing through a 
superheater. 

The temperature of water and its steam when confined in contact 
and under pressure may be computed from the sixth root of the 
absolute pressure in inches of mercury, or the absolute pressure in 
pounds per square inch multiplied by 2.036. Multiply the sixth root 
of this product by 176.4, and from the last product subtract 100 for the 
temperature in Column 3 of the tables of the properties of saturated 
steam. 


































































































132 


STEAM ABOVE ATMOSPHERIC PRESSURE 


For example: 

(1) . . At 100 pounds absolute, |/pX 2.036 = 4/203.6. 

As the sixth root is the cube root of the square root of the number, 

then 4/203.6 = 14.2688, and the 4/14.2688 = 2.42516 X 176.4 = 427.7 - 
100 = 327.6°, as in Column 3. 

The specific heat of water (which has been assigned as 0), at the 
zero of absolute pressure and 32° F. of temperature, gradually in¬ 
creases in its heat-unit quantity, equivalent to its thermometric 
temperature, so that at 212° it has absorbed 180.5 heat-units per 
pound to raise its temperature from 32° to 212° F., with an increasing 
ratio throughout the range of pressures and temperatures in use. 
The formula for the specific heat of water as given by Regnault and 
Rankine for any temperature T, above 32° F., is 

(2) . . T — 32°+0.000,000,103 X[(T — 39.1) 3 + (7.1) 3 ] = the number 

of heat-units imparted to the water as represented in Column 4, Table 
XX, of the properties of saturated steam. 

The latent heat of vaporization of water, Column 5 in the steam 
table, is from Rankine’s formula: 

(3) . . L = 1,091.7 — (.698(t — 32°), in which t = the thermometric 

temperature in Column 3. 

The total amount of heat in steam, as in Column 6, consists of the 
amounts in Columns 4 and 5 added, and may be computed from the 
formula of Regnault, in which 

(4) . . H = 1,091.7 + (.305(t — 32°), t being the thermometric tem¬ 

perature in Column 3. For example: 

212°-32° = 180X.305 = 54.9, and 54.9 + 1,091.7 = 1,146.6, as in 
Column 6 of the table of properties of saturated steam. The specific 
heat of steam is uniform throughout the range of temperatures in 
contact with its water of generation, and is assigned as 0.305 
(water 1). 

The specific heat of steam may also be used for obtaining the 
heat-unit values in Column 6, Table XX. The latent heat of steam 
at zero pressure is 1,082 heat-units; then the temperature due to the 
absolute pressure multiplied by the specific heat, plus 1,082, equals 
the total units above 32° F. 






STEAM ABOVE ATMOSPHERIC PRESSURE 


133 


For example: (212°x.305) +1,082 = 1,146.6 heat-units, as in Col¬ 
umn 6; also at 100.3 gauge-pressure = 115 absolute, the temperature 
in Column 3: (337.9X.305)+ 1,082 = 1,185.05, and so on. 

Steam has its critical temperature at about 2,052° absolute 
(1,592° F.), above which the latent heat of evaporation will be zero and 
there would be no difference between the liquid and vaporous forms, 
as its liquid volume will have disappeared. 


The values in Columns 7, 8, and 9 are relative, so that 
Column 7 = - °! Umn ^ (weight of water per cubic foot); 


62.43 


Column 8 = 


, and Column 9= ^ ^ 


Column 7 


Column 8 


The volume of steam per pound of water at any temperature may 
be obtained from the formula: 


(5) 


V 2 = V! + 


He 


dp 

dt 


t, in which He = the foot-pound value 


of the latent heat in Column 5; V 2 = the volume of saturated steam 
in cubic feet; t = absolute temperature of water and steam; dp = dif¬ 
ferential pressure per square foot; dt = differential temperature or 
1° F.; Vi= volume of water at temperature t. 

The difference in pressure per degree F., at atmospheric pressure for 1 

dp .2945 

heat-unit, is—= —X144 = 42.408 pounds per square foot; then 

as water increases in volume .04775 per unit of heat from its maxi¬ 
mum density (39.1° F.), its volume per pound is therefore = 

0.01602 cubic foot. Then 0.01602 X 1.04775 = 0.01678, its increased 
volume for 1 heat-unit. 

The cubic feet of steam per pound of water at atmospheric pres¬ 
sure may be computed from the following formula: 

(6) . . 0.01678 + 6 72 6 6 6~§ 1 = 26.37, as in Column 7. 











134 


STEAM ABOVE ATMOSPHERIC PRESSURE 


For 30 pounds absolute pressure the difference in temperature per 
pound of pressure from Column 3 is 

(7) . . 1.886° F. a,nd-F- = .5302X144=76.35, the ratio. 

1.88b 

Then 0.01678 + = CCM = 13.458 + .017 = 13.475, as 


710.96X76.35 54,281.8 


in Column 7. 


For 100 pounds absolute the ratio will be — = 1.43X144 — 205.9. 

• 7 


(8) . . Then 0.01678 + ^||~g^ = 4.227 + .017 = 4.244. 

Again, for 200 pounds absolute, the ratio of pressure to dif¬ 
ferential temperature is —= 2.44 X144 = 351.3. 

(9) . . Then 0.01678 + gg|~g|^ = 2.217 + 0.017 = 2.234, the 

cutting off of fractions making a slight discrepancy from the tables 
as established. 

The total heat-units in Column 6 may be obtained directly from 
the temperature in Column 3 by the formula 

(10) . . 1,091.7+ .305 (Column 3)—32, in which 1,091.7 is the 

total value in heat-units of the vapor of water at the absolute zero 
of pressure, and .305 the specific heat of saturated steam. 

Then, for example, at 100 pounds absolute pressure, from the 
temperature in Column 3, we have, 

(11) . . 327.6 -32 = 295.6X.305 = 90.15 + 1,091.7 = 1,181.85, as 
in Column 6. 








135 


STEAM ABOVE ATMOSPHERIC 


PRESSURE 


Table XX. —Properties of Saturated Steam—Pressures, Temperature, 

Volume, Weight, etc. 


Barometer- 

vacuum, 

inches. 

Absolute 

pressure, 

pounds. 

Temperature 
of water, 
Fahrenheit. 

Heat-units 
from 32° F. 
to temp., 

Column 3. 

Latent heat 

of vaporiza¬ 

tion, units. 

Total heat, 

Columns 

4 and 5, 

units. 

Volume of 

1 pound, 

cubic feet. 

1 

2 

3 

4 

5 

6 

7 

2. 

035 

1 

102.0° 

70. 

0 

1,043. 

0 

1,113. 

0 

330. 

4 

4. 

07 

2 

126.3 

94. 

4 

1,026. 

1 

1,120 

5 

171. 

9 

6. 

105 

3 

141.7 

109. 

8 

1,015. 

4 

1,125. 

2 

117. 

8 

8. 

14 

4 

153.1 

121. 

3 

1,007. 

4 

1,128. 

7 

89. 

51 

10. 

175 

5 

162.4 

130. 

6 

1,000. 

9 

1,131. 

5 

72. 

56 

12. 

21 

6 

170.2 

138. 

4 

995. 

4 

1,133. 

8 

61. 

14 

14. 

245 

7 

176.9 

145. 

2 

990. 

7 

1,135. 

9 

52. 

89 

16. 

28 

8 

183.0 

151. 

3 

986. 

5 

1,137 

8 

46 

65 

18 

315 

9 

188.4 

156 

7 

982. 

7 

1,139. 

4 

41. 

77 

20 

35 

10 

193.3 

161 

7 

979. 

3 

1,141 

0 

37 

83 

22 

385 

11 

197.8 

166 

2 

976. 

1 

1,142 

3 

34 

59 

24 

42 

12 

202.0 

170 

5 

973 

1 

1,143 

6 

31 

87 

26 

455 

13 

205.9 

174 

4 

970 

4 

1,144 

8 

29 

56 

28 

49 

14 

209.6 

178 

1 

967 

8 

1,145 

9 

27 

58 

29 

92 

14.7 

212.0 

180 

5 

966 

1 

1,146 

6 

26 

37 


3 

15 

213.1 

181 

6 

965 

3 

1,146 

9 

25 

85 

& i 

3 

16 

216.3 

184 

9 

963 

0 

1,147 

9 

24 

33 

1 2 

3 

17 

219.5 

188 

1 

960 

8 

1,148 

9 

22 

98 

o 3 

.3 

18 

222.4 

191 

1 

958 

8 

1,149 

9 

21 

78 

4 

.3 

19 

225.3 

193 

9 

956 

7 

1,150 

6 

20 

70 

5 

.3 

20 

228.0 

196 

7 

954 

8 

1,151 

5 

19 

73 

6 

.3 

21 

230.6 

199 

3 

952 

9 

1,152 

2 

18 

84 

7 

.3 

22 

233.1 

201 

8 

951 

2 

1,153 

0 

18 

04 

8 

.3 

23 

235.5 

204 

3 

949 

5 

1,153 

8 

17 

30 

9 

.3 

24 

237.8 

206 

6 

947 

8 

1,154 

4 

16 

62 

10 

.3 

25 

240.1 

208 

9 

946 

3 

1,155 

2 

16 

00 

11 

.3 

26 

242.2 

211 

1 

944 

8 

1,155 

9 

15 

42 

12 

.3 

27 

244.3 

213 

2 

943 

o 

—j 

1,156 

4 

14 

88 

13 

.3 

28 

246.4 

215 

3 

941 

8 

1,157 

1 

14 

.38 

14 

.3 

29 

248.4 

217 

3 

940 

4 

1,157 

7 

13 

.91 

15 

.3 

30 

250.3 

219 

3 

939 

0 

1,158 

3 

13 

.48 

16 

.3 

31 

252.2 

221 

2 

937 

7 

1,158 

.9 

13 

.07 

17 

.3 

32 

254.0 

223 

0 

936 

4 

1,159 

.4 

12 

.68 

18 

.3 

33 

255.8 

224 

8 

935 

1 

1,159 

.9 

12 

.32 

19 

3 

34 

257.5 

226 

6 

933 

9 

1,160 

.5 

11 

.98 

20 

3 

35 

259.2 

228 

3 

932 

7 

1,161 

.0 

11 

.66 

21 

3 

36 

260.9 

230 

0 

931 

5 

1,161 

.5 

11 

.36 

22 

3 

37 

262.5 

231 

7 

930 

4 

1,162 

.1 

11 

.07 

23 

3 

38 

264.1 

233 

3 

929 

.3 

1,162 

.6 

10 

.79 

24 

3 

39 

265.6 

234 

8 

928 

.1 

1,162 

.9 

10 

.53 

25 

3 

40 

267.2 

236 

4 

927 

0 

1,163 

.4 

10 

.28 

26 

3 

41 

268.7 

237 

9 

926 

.0 

1,163 

.9 

10 

. 05 

27 

3 

42 

270.1 

239 

4 

924 

.9 

1,164 

.3 

9 

.826 

28 

3 

43 

271.6 

240 

8 

923 

.9 

1,164 

.7 

9 

.609 

29. 

3 

44 

273.0 

242 

3 

922 

.9 

1,165 

.2 

9 

.403 

30. 

3 

45 . 

274.3 

243 

7 

921 

.9 

1,165 

.6 

9 

.207 


Weight of 

1 cubic 

foot of steam. 

Relative 

volume to 

water. 

8 

9 

.00303 

20,628 

.00582 

10,730 

.00852 

7,325 

.01117 

5,588 

.01378 

4,530 

.01636 

3,816 

.01891 

3,302 

.02144 

2,912 

.02394 

2,607 

.02644 

2,361 

.02891 

2,151 

.03138 

1,990 

.03383 

1,845 

.03626 

1,721 

.03793 

1,646 

.03869 

1,614 

.04111 

1,519 

.04352 

1,434 

.04592 

1,359 

.04831 

1,292 

.05070 

1,281 

.05307 

1,176 

.05545 

1,126 

.03781 

1,080 

.06017 

1,038 

.06252 

998.4 

.06487 

962.3 

.06721 

928.8 

.06955 

897.6 

.07188 

868.5 

.07420 

841.3 

.07652 

815.8 

.07884 

791.8 

.0S115 

769.2 

.08346 

748.0 

.08577 

727.9 

.08807 

708.8 

.09036 

690.8 

.09266 

673.7 

.09495 

657.5 

.09723 

642.0 

.09951 

627.3 

.10179 

613.3 

.10407 

599.9 

.10635 

587.0 

.10862 

574.7 











































136 


STEAM ABOVE ATMOSPHERIC PRESSURE 


Table XX. —Properties Saturated Steam—Pressures, Temperature, 

Volume, Weight, etc.—( Continued .) 


Gauge 

pressure, 

pounds. 

Absolute 

pressure, 

pounds. 

Temperature 
of water, 
Fahrenheit. 

Heat-units 

from 32° F. 

to temp., 

Column 3. 

Latent heat 

of vaporiza¬ 

tion, units. 

Total heat, 

Columns 

4 and 5, 

units. 

Volume of 

1 pound, 

cubic feet. 

Weight of 

1 cubic 

foot of steam. 

Relative 

volume to 

water. 

1 

2 

3 

4 

! 5 

6 

7 

8 

9 

31.3 

46 

' 275.7° 

245.1 

920.9 

1,166.0 

9.018 

.11088 

563.0 

32.3 

47 

277.0 

246.4 

920.0 

1,166.4 

8.838 

.11315 

551.7 

33.3 

48 

278.3 

247.8 

919.1 

1,166.9 

8.665 

.11541 

540.9 

34.3 

49 

279.6 

249.1 

918.1 

1,167.2 

8.498 

.11767 

530.5 

35.3 

50 

280.9 

250.4 

917.3 

1,167.7 

8.338 

.11993 

520.5 

36.3 

51 

282.2 

251.6 

916.4 

1,168.0 

8.185 

.12218 

510.9 

37.3 

52 

283.4 

252.9 

915.5 

1,168.4 

8.037 

.12443 

501.7 

38.3 

53 

284.6 

254.1 

914.7 

1,168.8 

7.894 

.12668 

492.8 

39.3 

54 

285.8 

255.3 

913.8 

1,169.1 

7.756 

.12893 

484.2 

40.3 

55 

287.0 

256.5 

912.9 

1,169.4 

• 7.624 

.13112 

475.9 

41.3 

56 

288.1 

257.7 

912.1 

1,169.8 

7.496 

.13341 

467.9 

42.3 

57 

289.3 

258.9 

911.3 

1,170.2 

7.372 

.13565 

460.2 

43.3 

58 

290.4 

260.0 

910.5 

1,170.5 

7.252 

.13789 

452.7 

44.3 

59 

291.5 

261.1 

909.7 

1,170.8 

7.136 

.14013 

445.5 

45.3 

60 

292.6 

262.2 

908.9 

1,171.1 

7.024 

.14236 

438.5 

46.3 

61 

293.7 

263.3 

908.2 

1,171.5 

6.916 

.14459 

431.7 

47.3 

62 

294.7 

264.4 

907.4 

1,171.8 

6.811 

.14682 

425.2 

48.3 

63 

295.8 

265.5 

906.6 

1,172.1 

6.709 

.14905 

418.8 

49.3 

64 

296.8 

266.6 

905.9 

1,172.5 

6.610 

.15128 

412.6 

50.3 

65 

297.8 

267.6 

905.2 

1,172.8 

6.515 

.15350 

406.6 

51.3 

66 

298.8 

268.6 

904.4 

1,173.0 

6.422 

.15572 

400.8 

52.3 

67 

299.8 

269.7 

903.7 

1,173.4 

6.332 

.15794 

395.2 

53.3 

68 

300.8 

270.8 

903.0 

1,173.7 

6.244 

.16016 

389.8 

54.3 

69 

301.8 

271.7 

902.3 

1,174.0 

6.159 

.16237 

384.5 

55.3 

70 

302.8 

272.7 

901.6 

1,174.3 

6.076 

.16458 

379.3 

56.3 

71 

303.7 

273.6 

901.0 

1,174.6 

5.995 

.16679 

374.3 

57.3 

72 

304.7 

274.6 

900.2 

1,174.8 

5.917 

.16900 

369.4 

58.3 

73 

305.6 

275.6 

899.6 

1,175.2 

5.841 

.17121 

364.6 

59.3 

74 

306.5 

276.5 

898.9 

1,175.4 

5.767 

.17342 

360.0 

60.3 

75 

307.4 

277.4 

898.3 

1,175.7 

5.694 

.17562 

355.5 

61.3 

76 

308.3 

278.4 

897.7 

1,176.1 

5.624 

.17783 

351.1 

62.3 

77 

309.2 

279.3 

897.0 

1,176.3 

5.555 

.18003 

346.8 

63.3 

78 

310.1 

280.2 

896.4 

1,176.6 

5.488 

.18223 

342.6 

64.3 

79 

311.0 

281.1 

895.7 

1,176.8 

5.422 

.18443 

338.5 

65.3 

80 

311.9 

282.0 

895.1 

1,177.1 

5.358 

.18663 

334.5 

66.3 

81 

312.7 

282.8 

894.4 

1,177.3 

5.296 

.18882 

330.6 

67.3 

82 

313.6 

283.7 

893.9 

1,177.6 

5.235 

.19102 

326.8 

68.3 

83 

314.4 

284.6 

893.3 

1,177.9 

5.176 

.19321 

323.1 

69.3 

84 

315.3 

285.4 

892.7 

1,178.1 

5.118 

.19540 

319.5 

70.3 

85 

316.1 

286.3 

892.1 

1,178.4 

5.061 

.19759 

315.9 

71.3 

86 

316.9 

287.1 

891.5 

1,178.6 

5.006 

.19978 

312.5 

72.3 

87 

317.7 

287.9 

891.0 

1,178.9 

4.951 

.20197 

309.1 

73.3 

88 

318.5 

288.8 

890.3 

1,179.1 

4.898 

.20416 

305.8 

74.3 

89 

319.3 

289.6 

889.8 

1,179.4 

4.846 

.20634 

302.5 

75.3 

90 

320.1 

290.4 

889.2 

1,179.6 

4.796 

.20853 

299.4 





















































STEAM ABOVE ATMOSPHERIC PRESSURE 


137 


Table XX.—Properties of Saturated Steam—Pressures, Temperature, 

Volume, Weight, etc.—( Continued .) 


Gauge 

pressure, 

pounds. 

Absolute 

pressure, 

pounds. 

Temperature 
of water, 
Fahrenheit. 

Heat-units 
from 32° F. 
to temp., 
Column 3. 

Latent heat 

of vaporiza¬ 

tion, units. 

Total heat, 

Columns 

4 and 5, 

units. 

Volume of 

1 pound, 

cubic feet. 

Weight of 

1 cubic 

foot of steam. 

Relative 

volume to 

water. 

i 

1 

2 

3 

4 

5 

6 

7 

8 

9 

76.3 

91 

320.9° 

291.2 

888.7 

1,179.9 

4.746 

.21071 

296.3 

77.3 

92 

321.7 

292.0 

888.1 

1,180.1 

4.697 

.21289 

293.2 

78.3 

93 

322.4 

292.8 

887.6 

1,180.4 

4.650 

.21507 

290.2 

79.3 

94 

323.2 

293.5 

887.0 

1,180.5 

4.603 

.21725 

287.3 

80.3 

95 

323.9 

294.3 

886.4 

1,180.7 

4.557 

.21943 

284.5 

81.3 

96 

324.7 

295.1 

885.9 

1,181.0 

4.513 

.22160 

'281.7 

82.3 

97 

325.4 

295.8 

885.3 

1,181.2 

4.469 

.22378 

279.0 

83.3 

98 

326.2 

296.6 

884.8 

1,181.4 

4.426 

.22595 

276.3 

84.3 

99 

326.9 

297.4 

884.3 

1,181.7 

4.384 

.22812 

273.7 

85.3 

100 

327.6 

298.1 

883.8 

1,181.9 

4.342 

.23029 

271.1 

86.3 

101 

328.3 

298 .'8 

883.2 

1,182.0 

4.302 

.23246 

268.5 

87.3 

102 

329.1 

299.6 

882.8 

1,182.3 

4.262 

.23463 

266.0 

88.3 

103 

329.8 

300.3 

882.2 

1,182.5 

4.223 

.23680 

263.6 

89.3 

104 

330.5 

301.0 

881.7 

1,182.7 

4.185 

.23897 

261.2 

90.3 

105 

331.2 

301.7 

881.2 

1,182.9 

4.147 

.24114 

258.9 

91.3 

106 

331.9 

302.4 

880.7 

1,183.1 

4.110 

.24330 

256.6 

92.3 

107 

332.6 

303.2 

880.3 

1,183.5 

4.074 

.24547 

254.8 

93.3 

108 

333.2 

303.9 

879.7 

1,183.6 

4.038 

.24763 

252.1 

94.3 

109 

333.9 

304.6 

879.2 

1,183.8 

4.003 

.24979 

249.9 

95.3 

110 

334.6 

305.2 

878.8 

1,184.0 

3.969 

.25195 

247.8 

96.3 

111 

335.3 

305.9 

878.3 

1,184.2 

3.935 

.25411 

245.7 

97.3 

112 

335.9 

306.6 

877.7 

1,184.3 

3.902 

.25626 

243.6 

98.3 

113 

336.6 

307.3 

877.3 

1,184.6 

3.870 

.25842 

241.6 

99.3 

114 

337.2 

308.0 

876.8 

1,184.8 

3.838 

.26058 

239.6 

100.3 

115 

337.9 

308.6 

876.4 

1,185.0 

3.806 

.26273 

237.6 

101.3 

116 

338.5 

309.3 

875.9 

1,185.2 

3.775 

.26489 

235.7 

102.3 

117 

339.2 

309.9 

875.4 

1,185.3 

3.745 

.26704 

233.8 

103.3 

118 

339.8 

310.6 

875.0 

1,185.6 

3.715 

.26920 

231.9 

104.3 

119 

340.4 

311.2 

874.5 

1,185.7 

3.685 

.27135 

230.1 

105.3 

120 

341.1 

311.9 

874.0 

1,185.9 

3.656 

.27350 

228.3 

106.3 

121 

341.7 

312.5 

873.7 

1,186.2 

3.628 

.27565 

226.5 

107.3 

122 

342.3 

313.2 

873.2 

1,186.4 

3.600 

.27780 

224.7 

108.3 

123 

342.9 

313.8 

872.7 

1,186.5 

3.572 

.27995 

223.0 

109.3 

124 

343.5 

314.4 

872.3 

1,186.7 

3.545 

.28210 

221.3 

110.3 

125 

344.1 

315.1 

871.8 

1,186.9 

3.518 

.28424 

219.6 

111.3 

126 

344.7 

315.7 

871.4 

1,187.1 

3.492 

.28639 

218.0 

112.3 

127 

345.3 

316.3 

871.0 

1,187.3 

3.466 

.28853 

216.4 

113.3 

128 

345.9 

316.9 

870.5 

1,187.4 

3.440 

.29068 

214.8 

114.3 

129 

346.5 

317.5 

870.0 

1,187.6 

3.415 

.29282 

213.2 

115.3 

130 

347.1 

318.1 

869.5 

1,187.8 

3.390 

.29496 

211.6 

116.3 

131 

347.6 

318.7 

868.9 

1,188.0 

3.370 

.29700 

210.1 

117 3 

132 

348.2 

319.3 

868.3 

1,188.2 

3.355 

.29900 

208.6 

118 3 

133 

348.8 

319.9 

867.9 

1,188.3 

3.340 

.30060 

207.1 

119 3 

134 

349.4 

320.6 

867.5 

1,188.5 

3.328 

.30220 

205.7 

120.3 

135 

350.0 

321.3 

867.0 

1,188.7 

3.304 

.30580 

204.2 


















































138 


STEAM ABOVE ATMOSPHERIC PRESSURE 


Table XX. —Properties oi<> Saturated Steam—Pressures, Temperature, 

Volume, Weight, etc.—( Continued .) 


Gauge 

pressure, 

pounds. 

Absolute 

pressure, 

pounds. 

Temperature 
of water, 
Fahrenheit. 

Heat-units 

from 32° F. 

to temp., 

Column 3. 

Latent heat 

of vaporiza¬ 

tion, units. 

Total heat, 

Columns 

4 and 5, 

units. 

Volume of 

1 pound, 

cubic feet. 

Weight of 

1 cubic 

foot of steam. 

Relative 

volume to 

water. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

121.3 

136 

350.5° 

321.9 

867.6 

1,188.9 

3.280 

.30840 

202.8 

122.3 

137 

351.1 

322.5 

867.1 

1,189.0 

3.260 

.31045 

201.4 

123.3 

138 

351.8 

323.1 

866.6 

1,189.2 

3.240 

.31292 

200.0 

124.3 

139 

352.2 

323.7 

866.1 

1,189.4 

3.220 

.31313 

198.7 

125.3 

140 

352.8- 

324.3 

865.6 

1,189.6 

3.201 

.31534 

197.3 

126.3 

141 

353.3 

325.0 

865.1 

1,189.7 

3.182 

.31752 

196.0 

127.3 

142 

353.9 

325.7 

864.5 

1,189.9 

3.163 

.31950 

194.7 

128.3 

143 

354.4 

326.3 

863.9 

1,190.0 

3.144 

.32110 

193.4 

129.3 

144 

355.0 

327.1 

863.2 

1,190.2 

3.123 

.32320 

192.2 

130.3 

145 

355.5 

327.8 

862.6 

1,190.4 

3.101 

.32530 

190.9 

131.3 

146 

356.0 

328.4 

862.2 

1,190.5 

3.067 

.3274 

189.7 

132.3 

147 

356.6 

328.9 

861.8 

1,190.7 

3.050 

.3295 

188.5 

133.3 

148 

357.1 

329.5 

861.4 

1,190.9 

3.03 

.3316 

187.3 

134.3 

149 

357.6 

330.0 

861.0 

1,191.0 

3.01 

.3337 

186.1 

135.3 

150 

358.2 

330.6 

860.6 

1,191.2 

2.99 

.3358 

184.9 

136.3 

151 

358.7 

331.1 

860.2 

1,191.3 

2.97 

.3379 

183.7 

137.3 

152 

359.2 

331.6 

859.9 

1,191.5 

2.95 

.3400 

182.6 

138.3 

153 

359.7 

332.2 

859.5 

1,191.7 

2.93 

.3421 

181.5 

139.3 

154 

360.2 

332.7 

859.1 

1,191.8 

2.91 

.3442 

180.4 

140.3 

155 

360.7 

333.2 

858.7 

1,192.0 

2.89 

.3463 

179.2 

141.3 

156 

361.1 

333.8 

858.4 

1,192.1 

2.87 

.3483 

178.1 

142.3 

157 

361.8 

334.3 

858.0 

1,192.3 

2.85 

.3504 

177.0 

143.3 

158 

362.3 

334.8 

857.6 

1,192.4 

2.84 

.3525 

176.0 

144.3 

159 

362.8 

335.3 

857.2 

1,192.6 

2.82 

.3546 

174.9 

145.3 

160 

363.3 

335.9 

856.9 

1,192.7 

2.80 

.3567 

173.9 

146.3 

161 

363.8 

336.4 

856.5 

1,192.9 

2.79 

.3588 

172.9 

147.3 

162 

364.3 

336.9 

856.1 

1,193.0 

2.77 

.3609 

171.9 

148.3 

163 

364.8 

337.4 

855.8 

1,193.2 

2.76 

.3630 

171.0 

149.3 

164 

365.3 

337.9 

855.4 

1,193.3 

2.74 

.3650 

170.0 

150.3 

165 

365.7 

338.4 

855.1 

1,193.5 

2.72 

.3671 

169.0 

151.3 

166 

366.2 

338.9 

854.7 

1,193.6 

2.71 

.3692 

168.1 

152.3 

167 

366.7 

339.4 

854.4 

1,193.8 

2.69 

.3713 

167.1 

153.3 

168 

367.2 

339.9 

854.0 

1,193.9 

2.68 

.3734 

166.2 

154.3 

169 

367.7 

340.4 

853.6 

1,194.1 

2.66 

.3754 

165.3 

155.3 

170 

368.2 

340.9 

853.3 

1,194.2 

2.65 

.3775 

164.3 

156.3 

171 

368.6 

341.4 

852.9 

1,194.4 

2.63 

.3796 

163.4 

157.3 

172 

369.1 

341.9 

852.6 

1,194.5 

2.62 

.3817 

162.5 

158.3 

173 

369.6 

342.4 

852.3 

1,194.7 

2.61 

.3838 

161.6 

159.3 

174 

370.0 

342.9 

851.9 

1,194.8 

2.59 

.3858 

160.7 

160.3 

175 

370.5 

343.4 

851.6 

1,194.9 

2.58 

.3879 

159.8 

161.3 

176 

371.0 

343.9 

851.2 

1,195.1 

2.56 

.3900 

158.9 

162.3 

177 

371.4 

344.3 

850.9 

1,195.2 

2.55 

. 3921 

158.1 

163.3 

178 

371.9 

344.8 

850.5 

1,195.4 

2.54 

.3942 

157.2 

164.3 

179 

372.4 

345.3 

850.2 

1,195.5 

2.52 

. 3962 

156.4 

165 3 

180 

372.8 

345.8 

849.9 

1,195.7 

2.51 

.3983 

155.6 


















































STEAM ABOVE ATMOSPHERIC PRESSURE 


139 


Table XX. —Properties of Saturated Steam—Pressures, Temperature, 

Volume, Weight, etc.—( Continued .) 


Gauge 

pressure, 

pounds. 

Absolute 

pressure, 

pounds. 

Temperature 
of water, 
Fahrenheit. 

Heat-units 
from 32° F. 
to temp., 
Column 3. 

i 

Latent heat 

of vaporiza¬ 

tion, units. 

Total heat, 

Columns 

4 and 5, 

units. 

Volume of 

1 pound, 

cubic feet. 

Weight of 

1 cubic 

foot of steam. 

Relative 

volume to 

water. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

166.3 

181 

373.3° 

346.3 

849.5 

1,195.8 

2.50 

.4004 

154.8 

167.3 

182 

373.7 

346.7 

849.2 

1,195.9 

2.48 

.4025 

154.0 

168.3 

183 

374.2 

347.2 

848.9 

1,196.1 

2.47 

.4046 

153.2 

169.3 

184 

374.6 

347.7 

848.5 

1,196.2 

2.46 

.4066 

152.4 

170.3 

185 

375.1 

348.1 

848.2 

1,196.3 

2.45 

.4087 

151.6 

171.3 

186 

375.5 

348.6 

847.9 

1,196.5 

2.43 

.4108 

150.8 

172.3 

187 

375.9 

349.1 

847.6 

1,196.6 

2.42 

.4129 

150.0 

173.3 

188 

376.4 

349.5 

847.2 

1,196.7 

2.41 

.4150 

149.2 

174.3 

189 

376.9 

350.0 

846.9 

1,196.9 

2.40 

.4170 

148.5 

175.3 

190 

377.3 

350.4 

846.6 

1,197.0 

2.39 

.4191 

147.8 

176.3 

191 

377.7 

350.9 

846.3 

1,197.1 

2.37 

.4212 

147.0 

177.3 

192 

378.2 

351.3 

845.9 

1,197.3 

2.36 

.4233 

146.3 

178.3 

193 

378.6 

351.8 

845.6 

1,197.4 

2.35 

.4254 

145.6 

179.3 

194 

379.0 

352.2 

845.3 

1,197.5 

2.34 

.4275 

144.9 

180.3 

195 

379.5 

352.7 

845.0 

1,197.7 

2.33 

.4296 

144.2 

181.3 

196 

380.0 

353.1 

844.7 

1,197.8 

2.32 

.4317 

143.5 

182.3 

197 

380.3 

353.6 

844.4 

1,197.9 

2.31 

.4337 

142.8 

183.3 

198 

380.7 

354.0 

844.1 

1,198.1 

2.29 

.4358 

142.1 

184.3 

199 

381.2 

354.4 

843.7 

1,198.2 

2.28 

.4379 

141.4 

185.3 

200 

381.6 

354.9 

843.4 

1,198.3 

2.27 

.4400 

140.8 

190.3 

205 

383.7 

357.1 

841.9 

1,199.0 

2.22 

.4503 

137.5 

195.3 

210 

385.7 

359.2 

840.4 

1,199.6 

2.17 

.4605 

134.5 

200.3 

215 

387.7 

361.3 

838.9 

1,200.2 

2.12 

.4707 

131.5 

205.3 

220 

389.7 

362.2 

838.6 

1,200.8 

2.06 

.4852 

128.7 

215.3 

230 

393.6 

366.2 

835.8 

1,202.0 

1.98 

.5061 

123.3 

225.3 

240 

397.3 

370.0 

833.1 

1,203.1 

1.90 

.5270 

118.5 

235.3 

250 

400.9 

373.8 

830.5 

1,204.2 

1.83 

.5478 

114.0 

285.3 

300 

417.4 

390.9 

818.3 

1,209.2 

1.535 

.6515 

95.8 

335.3 

350 

432.0 

406.3 

807.5 

1,213.7 

1.325 

.7545 

82.7 

385.3 

400 

444.9 

419.8 

797.9 

1,217.7 

1.167 

.8572 

72.8 

435.3 

450 

456.6 

432.2 

789.1 

1,221.3 

1.042 

.9595 

65.1 

485.3 

500 

467.4 

443.5 

781.0 

1,224.5 

.942 

1.062 

58.8 

535.3 

550 

477.5 

454.1 

773.5 

1,227.6 

.859 

1.164 

53.6 

585.3 

600 

486.9 

464.2 

766.3 

1,230.5 

.790 

1 .266 

49.3 

635.3 

650 

495.7 

473.6 

759.6 

1,233.2 

.731 

1.368 

45.6 

685.3 

700 

504.1 

482.4 

753.3 

1,235.7 

.680 

1.470 

42.4 

735.3 

750 

512.1 

490.9 

747.2 

1,238.0 

.636 

1.572 

39.6 

785.3 

800 

519.6 

498.9 

741.4 

1,240.3 

.597 

1.674 

37.1 

835.3 

850 

526.8 

506.7 

735.8 

1,242.5 

.563 

1.776 

34.9 

885.3 

900 

533.7 

514.0 

730.6 

1,244.7 

.532 

1.878 

33.0 

935.3 

950 

540.3 

521.3 

725.4 

1,246.7 

.505 

1.980 

31.4 

985.3 

1,000 

546.8 

528.3 

720.3 

1,248.7 

.480 

2.082 

30.0 













































FLOW OF STEAM THROUGH ORIFICES, NOZLES, AND PIPES 


The flow of steam from an orifice into a vacuum may be com¬ 
puted with approximate accuracy by the formula: 

(12) . . . 4 /T + 460.6 X 60.2, or the square root of the absolute 

temperature multiplied by 60.2, and the product by .54, the coefficient 
for the velocity at initial density for an orifice. 

For example: at 75 pounds absolute pressure, 60 pounds gauge- 
pressure, the temperature is 307.4, and 

/307.4 + 460.6 = i // 768 = 27.712 x 60.2 = 1,667 X .54 = 899.7, 
velocity of steam at its initial density. 

Into the atmosphere, steam flows through a thin plate-orifice, at 
its initial density due to its absolute pressure, with a velocity of 
3.5953 4 /height in feet of a column of steam, uniform in density, 
equal to its weight at its initial pressure per square foot. The height 
is equal to the volume of 1 pound of steam, as in Column 7, Table 
XX, of the properties of saturated steam, multiplied by 144 square 
inches in 1 square foot. For example: 

For 100 pounds absolute pressure it 
is 100 X4 .342 X144 = 62,524.8 feet, and 
4/62,524.8 = 250.7x3.5953 = 901.3 feet per 
second. 

The velocity of the jet of steam from 
an orifice or nozle is increased in the ratio 
of 1.624, so that in a short straight nozle, 
Fig. 120, of from two to two and one-half 
times its diameter in length, with good 
entrance-curves, the velocity may be 901 X 1.624 = 1,463 feet. In the 
expanding nozles, as designed for steam-turbines of the Delaval class, 
a much higher velocity is claimed. 

The velocity of flow of steam in pipes depends upon the pressure- 
head, which is the height in feet of a column of steam of a uniform 



Fig. 120.—Straight nozle. 
















FLOW OF STEAM THROUGH 


ORIFICES, NOZLES, AND PIPES 


141 


density of the steam at the entrance of the pipe—the length and 
diameter of the pipe in feet—a fractional exponent—and the head 
against which it is flowing at the terminal. 

The formula much in use for steam flowing from a long pipe into 
the atmosphere is: 


(13) 



d = velocity in feet per second. 


L and d = length and diameter of the pipe in feet or decimals 
of a foot for d. 

Then, as in the previous example, for 100 feet in length of a 
1-inch pipe, and boiler-pressure of 100 pounds absolute, 85.3 gauge, 
the height h, as before explained, is 62,524.8, and 

K9 a o __ 

V —h : X .0833 - 4 / 70.6 = 8.402 X50 = 400.1 feet per second. 


The acceleration in velocity of steam by its expansive effort in 
passing from a converging section to and through a diverging section 
of a jet-nozle, such as used for impulse energy in steam-turbines, 



is due to its expansive volume being greater than the increasing area 
of the diverging walls of the nozle, less the loss by cooling, as the 
expansion is adiabatic. From the general formula \/T + 460.6 X60.2 
for 75 pounds absolute pressure, the velocity at initial pressure gives 
1,667 feet per second in the throat of an expanding nozle. Then 
the relative volumes per pound, of steam at 75 pounds and atmos¬ 
pheric pressure, is: *£ - = 4.63; and if the relative areas of the ex- 

5.69 

panding nozle are as 1 to 2, the volume at the mouth of the nozle 






















142 FLOW OF STEAM THROUGH ORIFICES, NOZLES, AND PIPES 


will be: —=2.315, and deducting the shrinkage from the adiabatic 

Lj 

expansion, 2.315 1-3 = 1.78; then 1,667x1.78 = 2,968 feet per second. 


Fig. 123 shows the diverging forms of nozles for impact-wheels, in 
which the angle of impact should be as near 20° from the plane of 
rotation as possible. 

It is claimed, as stated by D. K. Clark, that when steam flows 
from a nozle of the best form, “the velocity does not increase when 
flowing into a resisting medium at any pressure below 58 per cent. 




Fig. 123.—Diverging nozles. 


Fig. 124.—Nozle of best form. 



of the initial pressure.” Then 160 pounds absolute pressureX58 
per cent. =92.8 pounds absolute, the lowest resisting pressure at 
which the velocity ceases to increase. 


The ratio of the volumes at these pressures is: 


46 

2.8 


1.643. 


Then, 


using the temperature formula 4 /T +460.6x60.2 for 160 pounds 
absolute pressure, we have 


28.7 X 60.2 = 1,727.7 X. 58 = 1,002x1.643 = 1,646 feet per second. 

Again using the formula 3.5953 4 /height, we have 160x2.8x144 
= 64,512 feet, and 

4 / 64,512 = 253.9 X3.5953 = 912.8, and 912.8x1.643 = 1,499 feet per 
second. 


In a diverging continuation of the nozle, as used for steam-turbines 
of the Delaval type, the acceleration in velocity due to expansion, 
less the adiabatic condition of expansion, will be in the ratio of the 
expanding-nozle areas at initial and terminal ends. Then if the ratio 
is 1 to 2, the velocity from the above equation should be: 1,499x2 = 
2,998 feet per second. 




























FLOW OF STEAM THROUGH ORIFICES, NOZLES, AND PIPES 143 

A formula deduced from Professor Rateau’s formula, based on 
the area of the entropy diagram for the velocity of steam in feet per 
second, is: 

(14) . . V=224|/(T 1 -T 2 )^+|^LA in which 


224 = 4 / 2gX778. 

Ti= absolute initial temperature of saturated steam; T 2 = absolute 
terminal temperature at, say, 100 + 460.6° F.; r = latent heat of vapor¬ 
ization at temperature Ti, as in Column 5 of steam table. Then from 
a nozle of best form with steam expanding from an initial pressure of 
160 pounds absolute into a vacuum of a little less than 1 pound ab¬ 
solute pressure, or 28 inches of mercury, at which pressure the absolute 
temperature T 2 = 100 + 460.6 = 560.6, and substituting figures for the 
letters in the formula, we have for 160 pounds absolute: 


224 y 823.9 — 560.6— + t^oq/q ^ = 4,027, the velocity in feet per 

\824.2 1,384.8/ 

second. 

The following table has been computed for velocities from a 
pressure of 160 pounds absolute, expanded to various stages of lower 
pressure by Rateau’s formulas, in which the figures in the tables of 
properties of saturated steam were used. For the dryness of steam 
from condensation, 1 = dry saturated steam, and 1 — x = the per¬ 
centage of moisture or condensation by expansion. 

This is found by the formula: 


(15) 


T 2 /l. h. T, 


T \ 

. . m „ +hy. log. -A) =x, the relative amount 

1. h. 1 2 \ 11 1 2 / 

of dry steam after expansion, in which T 2 is absolute temperature 
after expansion; Ti absolute initial temperature; 1. h. Ti. 2 , latent 
heat of vaporization, as in Column 5, steam table XX. 

For example, substituting the values for expansion from 160 
pounds absolute to atmospheric pressure, we have: 


672.6 / 856.9 
966.1 \824.2 


+ hy. log. 


824.2 X _ ^ 
672.6 ) X ’ 


as in Table XXI. 


For the area of a nozle of best form, as in Column 9 of Table 
XXI, the formula is: (Column 8), multiplied by the square inches 

in a foot, and the product divided by the product of the density and 
















144 FLOW OF STEAM THROUGH ORIFICES, NOZLES, AND PIPES 


Table XXL —Theoretical Velocity and Areas of an Expanding Nozle of 
Best Form for Dry Steam, Expanded from 160 Pounds Absolute Pres¬ 
sure per Square Inch to Lower Pressures. 


Pressure 
absol’te, 
lbs. per 
sq. in. 

t 2 , 

absolute 

degrees 

F. 

T.-T,, 

degrees 

F. 

D, 

lbs. per 
cu. ft. 

Vel., 
ft. per 
sec. 

D V 

p 

P 

x, 

per cent, 
dry. 

A, area 
of nozle, 
sq.in. 

Profile 

of 

nozle. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

160 

823 9 


. 3567 




1.000 

1.000 

2.31 

150 

818.8 

5.1 

.3358 

519 

174.2 

.937 

.992 

.818 

1.86 

140 

813.4 

10.5 

.3153 

745 

234.8 

.875 

.987 

.609 

1.38 

130 

807.7 

16.2 

.2949 

916 

270.1 

.812 

.982 

.524 

1.21 

120 

801.7 

22.2 

.2735 

1,088 

297.5 

.750 

.975 

.472 

1.09 

110 

795.2 

28.7 

.2519 

1,236 

311.3 

.687 

.969 

.448 

1.03 

100 

788.2 

35.7 

.2303 

1,383 

318.5 

.625 

.963 

.444 

1.02 

90 

780.7 

43.2 

.2085 

1,525 

317.9 

.562 

.957 

.433 

1.00 

70 

763.4 

60.5 

.1645 

1,813 

298.3 

.437 

.942 

.454 

1.04 

50 

741.5 

82.4 

.1199 

2,129 

255.1 

.312 

.923 

.521 

1.20 

30 

710.9 

113.0 

.0742 

2,525 

187.3 

.187 

.894 

.740 

1.70 

15 

673.7 

150.2 

.0386 ' 

2,934 

112.9 

.094 

.865 

1.103 

2.54 

5 

623.0 

200.9 

.0137 

3.412 

47.3 

.031 

.817 

2.489 

5.72 

2 

586.9 

237.0 

.0058 

3,752 

21.7 

.012 

.786 

5.202 

12.01 

1 

562.6 

261.3 

.00303 

4,027 

12.2 

.006 

.769 

9.07 

20.94 


velocity in Column 6. The weight of steam discharged per second 
per square inch of area will be: in pounds. 


x 144 


The proportional diameters of an expanding nozle for the theo¬ 
retical expansion of steam, from 160 pounds absolute, is given in Column 
10, and its form shown in Fig. 125, which is a profile of an expanding 



Fig . 125.—Theoretical curves of expanding nozles. 


nozle to meet the conditions of velocity and expansion. In practice, 
the expanding part of the nozle is much reduced in order to increase its 
velocity by reducing the lateral expansion. Fig. 125 shows the theo¬ 
retical profile of an expanding nozle in which the practical lines of the 
expanding part are shown by the dotted lines as used for turbine-nozles. 

































































FLOW OF STEAM THROUGH ORIFICES, NOZLES, AND PIPES 145 


ENERGY O F STEA M 

The theoretical energy of steam in foot-pound power is clue to the 
difference in the heat-unit values between' which it is expanded, 
and which, multiplied by 778, the foot-pound value per heat-unit, 
equals the total foot-pound value due to expansion per pound of 
steam. For example: the heat-units in 1 pound of steam at 160 
pounds absolute are 1,192.7, and the heat-units in 1 pound at 
atmospheric pressure are 966.1; then, 1,192.7 —966.1 =226.6x778 = 

176 294 

176,294 foot-pounds, and 1 ~' - = 5.34 horse-power per pound of 

oOjUUU 

steam per minute. 


FLOW OF STEAM THROUGH LONG PIPES 


The weight and volume of steam which will flow through a pipe 
in one minute from a given pressure, and any designated loss of 
pressure from friction, may be obtained from the following general 
formula for the flow of gases and vapors: 


(16) . . . . 




Llf 


W = total weight in pounds, which, divided by the weight of 1 cubic 
foot = cubic feet per minute; D = density or weight per cubic foot 
at initial pressure, pi; p 2 = terminal pressure at end of pipe; cl = 
actual diameter of the pipe in inches; L = length of pipe in feet. 

The following table represents the weight of steam that will flow 
per minute through a straight, smooth pipe of 240 times its internal 
diameter, with a loss of 1 pound in the pressure: 

For sizes of pipe less than 6 inches, the flow is calculated from 
the actual areas of “standard” pipe of such nominal diameters. 

For horse-power, multiply the figures in the table by 2. For any 
other loss of pressure, multiply by the square root of the given loss. 
For any other length of pipe, divide 240 by the given length expressed 
in diameters, and multiply the figures in the table by the square root of 
this quotient, which will give the flow for 1 pound loss of pressure. 
Conversely, dividing the given length by 240 will give the loss o^ 
pressure for the flow given in the table. 






146 FLOW OF STEAM THROUGH ORIFICES, NOZLES, AND PIPES 


Table XXII . —Flow of Steam ^Through Pipes of 240 Times Their Diameter, 

with a Loss of 1 Pound in Pressure. 


£1 



Diameter of pipe in 

inches. 



Length 

of each 

= 240 diameters. 



i 5 c 

m 3 •<- 
£ ° £ 

1 

1 

1 

2 

2 

2 

2 

3 

4 

5 

6 


8 

10 

12 

03 4 ) r* 

'3 3 




Weight of 

i 

steam per minute in pounds, 

ith 

1 pound loss 

of 

pressure. 



1 

2 

07 

5 

.7 

10 

27 

15 

45 

25 

.38 

46 

85 

77 

.3 

115 

.9 

211 

.4 

341 

.1 

502 

.4 

10 

2 

.57 

7 

.1 

12 

72 

19 . 

15 

31 

.45 

58 

05 

95 

.8 

143 

6 

262 

.0 

422 

.7 

622 

.5 

20 

3 

02 

8 

.3 

14 . 

94 

22 . 

49 

36 

.94 

68 

20 

112 

.6 

168 

7 

307 

.8 

496 

.5 

731 

3 

30 

3 

.40 

9 

.4 

16 . 

84 

25 . 

35 

41 

.63 

76 . 

84 

126 

.9 

190 

1 

346 

.8 

559 

.5 

824 

.1 

40 

3 

74 

10 

.3 

18 . 

51 

27 . 

87 

45 

.77 

84 . 

49 

139 

.5 

209 

0 

381 

.3 

615 

.3 

906 

0 

50 

4 

04 

11 

.2 

20 . 

01 

30 . 

13 

49 

.48 

91 . 

34 

150 

.8 

226 

0 

412 

2 

665 

.0 

979 

5 

60 

4 

32 

11 

.9 

21 . 

38 

32 . 

19 

52 

.87 

97 . 

60 

161 

.1 

241 

5 

440 

.5 

710 

.6 

1,046 

7 

70 

4 

58 

12 

.6 

22 . 

65 

34 . 

10 

56 

.00 

103 . 

37 

170 

.7 

255 

8 

466 

.5 

752 

.7 

1,108 

5 

80 

4 

82 

13 

.3 

23 . 

82 

35 . 

87 

58 

.91 

108 . 

74 

179 

.5 

269 

0 

490 

7 

791 

.7 

1,166 

1 

90 

5 

04 

13 

.9 

24 . 

92 

37 . 

52 

61 

.62 

113 . 

74 

187 

.8 

281 

4 

513 

3 

828 

.1 

1,219 

8 

100 

5 

25 

14 

.5 

25 . 

96 

39 

07 

64 

.18 

118 . 

47 

195 

.6 

293 

1 

534 

.6 

862 

.6 

1,270 

1 

120 

5 

63 

15 

.5 

27 . 

85 

41 . 

93 

68 

.87 

127 . 

12 

209 

.9 

314 

5 

573 

7 

925 

.6 

1,363 

3 

150 

6 

14 

17 

.0 

30 . 

37 

45 . 

72 

75 

.09 

138 . 

61 

228 

.8 

343 

0 

625 

.5 

1,009 

.2 

1 , 486 . 

5 


The loss of head due to the friction of the steam entering the pipe, 
and passing elbows and valves, will reduce the flow given in the table. 
The resistance at the opening, and that at a globe-valve, are each 
abmit the same as that for a length of pipe equal to 114 diameters 
di/ided by a number represented by 1 + (3.6diameter). For the 
sizes of pipes given in the table, these corresponding lengths are: 


1 

1 2 

2 

2 i 

3 

4 

5 

6 

8 

10 

12 

25 

34 

41 

47 

52 

60 

66 

71 

79 

84 

88 


The resistance at an elbow is equal to two-thirds that of a globe- 
valve. These equivalents—for opening, for elbows, and for valves— 
must be added in each instance to the actual length of pipe. Thus a 
4-inch pipe, 120 diameters (40 feet) long, with a globe-valve and three 
elbows, would be equivalent to 120 + 60 + 60 + (3 X 40) = 360 diameters 
long; and 330^240 = 1^. It would therefore have 1^ pounds loss of 
pressure at the flow given in the table, or deliver (1 -fVlJ = .816) =81.6 
per cent, of the steam with the same (1 pound) loss of pressure. 






























































CHAPTER XI 


SUPERHEATED STEAM AND ITS WORK 

Saturated steam, or steam which has exactly the temperature 
due to its pressure, has aptly been described as steam saturated with 
heat, and the chief peculiarity which it possesses is that the slightest 
abstraction of heat is followed by a corresponding condensation. 

Superheated steam is generated by the addition of heat to satu¬ 
rated steam. The behavior of superheated steam is similar to that of 
gases; it is a poor conductor of heat, and has the special peculiarity of 
losing a certain amount of heat without becoming saturated or wet 
steam. The specific heat of steam is only 0.48, and therefore very 
little heat is required to superheat steam; but as the steam loses 

b 

the heat as quickly as it acquires it, every passage conveying super¬ 
heated steam should be well covered with non-conducting material. 
Although there are some losses on account of the heat-radiation 
when using superheated steam, they are very much smaller per volume, 
because the loss of heat from superheated steam has lower calorific 
value than the latent heat of saturated steam. 

The economy effected by using superheated steam in engines is 
remarkable, and, acknowledging this fact, a great number of steam- 
users superheat the steam, although in many cases only a few degrees; 
yet a considerable saving in steam and coal is always the result. To 
obtain the full benefit, the required temperature of superheat should 
be 600° F., and to stand this temperature the engines should be 
specially designed. 

The use of highly superheated steam does not require high boiler- 
pressures; 160 pounds is the highest to be recommended, as no ad¬ 
vantage can be derived by exceeding this. As the amount of heat 
transmitted from the steam to cylinder-walls, and vice versa, is 
much lower with superheated steam than with saturated steam, the 
whole range of temperature from boiler-pressure to vacuum can take 
place in two cylinders, so that the use of a triple-expansion engine does 
not make very much improvement in economy. 


147 


148 


SUPERHEATED STEAM AND ITS WORK 

In view of the great advantages of steam-superlieating ; and the 
great number of engines running at present satisfactorily, it is aston¬ 
ishing that a few failures have caused prejudices among some engineers, 
who make the general introduction of the use of superheated steam 
very difficult. It will be worth mentioning that the lesults of a great 
number of trials have always proved a great saving in steam and 
coal, and even with small plants and simple piston-valve engines 
almost the same good economy is obtainable as with laige engines 
with most exact valve-gears. It is therefore recommended that 
superheated steam should be used in connection with all engines; 
the only question to be settled is the degree of superheat, which 
largely depends on local circumstances and the construction of the 
engine. 

Superheated-steam engines use on an average 30 to 40 per cent, 
less steam than saturated-steam engines of the same type. Con¬ 
sequently boilers can be made 30 per cent, smaller, and the difference 
in price will nearly cover the cost of the superheater. For the same 
steam-consumption the superheated-steam engine is cheaper, as it 
may be worked with a lower boiler-pressure. 

One of the most troublesome effects of expansion is found in the 
action of the steam-valves. Slide-valves and Corliss valves are nat¬ 
urally affected by the high temperatures, 480 to 500° F. being the 
upper limit for the latter. Piston-valves, when carefully constructed 
and proportioned, answer well, but they must be made especially 
for the service. The longitudinal expansion of the cylinder tends to 
deform the steam-chest and valve-seat, and provision must be made 
for such effects. Rings and springs in valves are objectionable, as 
it is difficult to keep the steam from getting between the rings and 
creating increased pressure and friction. Poppet-valves have been 
used with much success. 

The adoption of superheated steam in steam-engines was made 
possible by the manufacture of heavy mineral oils with high-ignition 
points and by the now common practice of using metallic packing. 
From a purely theoretical point of view the advantage gained is small, 
and if the conditions were those of the ideal engine, superheating would 
never have been heard of. On entering the cylinder of a steam-engine 
part of the steam is condensed, without doing any work, by coming in 
contact with the wails and piston, cooled from the previous exhaust- 


SUPERHEATED STEAM AND ITS WORK 


149 


stroke. This reduces tl 
cylinder with a film of 


io working value of the steam and coats the 
water, which conducts the heat much more 


readily to the cylinder-walls than in the case of dry steam. 

The principal object of superheating is to reduce this transfer of 
heat and initial condensation; for although the superheated steam 
gives up some of its heat to the metal on admission, there is no 
condensation, the only effect being a reduction of volume and a 
fall in temperature. Superheating also tends to prevent leakage at 
sliding surfaces, such as piston-rings, valves, etc. No matter how 
tight they are when at rest, a film of water, creeping along between 
the sliding surfaces, will cause steam to leak through when the 
engine is running. 

At 300° F. of superheat the volume of steam is increased about 
50 per cent., and owing to this increase in volume less heat is required 
to produce the same volume for superheated steam than for saturated 
steam at the same pressure. Thus less heat enters the cylinders at 
each stroke, and as the same amount of heat is converted into work 
in each case, the economy of superheating is apparent. 

It has been found that to attain a certain velocity of steam in a 
pipe, superheated steam requires a smaller drop in pressure than 
saturated steam and, as less steam is required per horse-power when 
superheated, a reduction may be made in the size of the piping, 
which again will reduce the cost as well as the loss from radiation. 

A separator will be unnecessary, which also reduces the radiating 
surface; and the absence of water in the steam-pipes does away with 
all risk of getting water into the cylinders. 

The superheater may have three different positions relative to the 
boiler: 1. It may be placed in the flue so as to extract heat from the 
gases as they leave the boiler, which is the most economical method of 
obtaining superheat. 2. It may be placed in the path of the gases 
between the fire and the boiler proper. 3. It may be quite separate, 
and independently fired. 

In case 1, a good boiler should take up enough of the heat from 
the gases to allow them to pass out at a temperature but little above 
that of the boiler. If only a low degree of superheat is required, this 
position is much the simplest and cheapest. 

Case 2 is the most economical method from point of view of fuel 
required, but the difficulty of regulating the temperature is much 


150 


SUPERHEATED STEAM AND ITS WORK 


greater. In Case 3 the temperature can be easily regulated and the 
superheater readily cut out when required. It is a more wasteful 
method than either of the other two, but as little coal is required 
by the superheater when compared with the boiler, the loss does not 
count for much. 

It may be taken as a general rule that the better the economy of 
an engine, the less gain there will be from superheat. Thus the best 
results should be looked for in a simple engine with a low steam- 
pressure. 

The question of the cost of the additional heat is sometimes raised, 
but it can be shown that much less heat is required to produce a cubic 
foot of superheated steam than to generate a cubic foot of saturated 
steam of the same pressure. 

In triple and quadruple expansion the gain is small unless the 
superheating is carried to a high temperature. It varies, of course, 
with the point of cut-off and the ratio of expansion. 

There is little gain due to superheating in any cylinder after the 
stage is reached in which the steam is kept dry throughout the whole 
expansion, the only object of taking the superheat higher is to obtain 
dry steam as far as possible during the whole expansion of the engine. 

The same effect may be obtained by reheating the steam in the 
receivers between the different cylinders, so that it will enter each 
cylinder superheated sufficiently to insure dryness at the end of the 
stroke in that cylinder. This can be effected by passing the super¬ 
heated steam through coils in the receiver, so as to give up part of its 
heat to the steam that has already expanded in the previous cylinder 
and pass on to the steam-chest of the engine at a lower degree of 
superheat. This method gives the advantage of a high degree of 
superheat without the disadvantage of extremely high temperature in 
the cylinders. 

The effect of superheating in turbines is somewhat different from 
that in engines. In some turbines the potential energy of the steam 
is transformed into kinetic energy before being available for doing 
work. This is effected by means of a large drop of pressure through a 
small nozle. Some of the heat appears as kinetic energy, and if 
saturated steam were used, there would be water present at this 
pressure. If superheated, the extra heat in the steam would prevent 
any condensation and increase the volume and velocity of the steam. 


SUPERHEATED STEAM AND ITS WORK 


151 


With this form of turbine the high-temperature steam never comes in 
contact with the frictional parts, and the only limit to the degree of 
superheat is apparently the temperature at which the strength of steel 
begins to be affected. Results of a trial have been published on a 
De Laval turbine using steam at 930° F., with no serious difficulties 
encountered. 

The ideal efficiency of a heat-engine is determined by the range of 
temperature through which it works and not by the medium through 
which that heat is used. This theoretical fact is employed as an argu¬ 
ment in favor of superheated steam. It is pretty generally recognized 
now that one of the losses of the steam-engine is the interchange of 
heat which goes on between the cylinder metal and the working steam. 
To prevent this interchange it is usual to superheat the steam so that 
less of it may turn into water, for it is in the form of water that the 
working fluid exerts its worst effects. 

Theorists who look on superheat as a means of raising the tempera¬ 
ture of the working fluid, overlook some important practical considera¬ 
tions. During the period of time that the admission-port of the 
cylinder is open, the piston of the engine is pushed forward by the 
pressure of the steam in the boiler. The steam in the pipe does not 
expand. It flows into the cylinder in obedience to the push which it 
receives from behind, and this push is not even due in all cases or 
entirely to expansion in the boiler. It is due directly to the heat of 
the fire, which causes the water to turn into steam. It is this bulk 
of new steam that pushes the engine-piston, and the steam between 
the boiler and the moving face of the piston is simply a strut; for, 
since it maintains a constant pressure, it cannot expand. In its 
passage from the boiler to the engine through a superheater it re¬ 
ceives additional heat per given volume of saturated steam, and 
expands to a new volume, due to the amount of superheat, without 
receiving any addition of water, and thereby assumes the condition of 
a gas. As a gas it does work by expansion, without loss from con¬ 
densation, until its temperature falls to the saturation-point, when 
its further expansion assumes the condition of saturated steam. 

Therefore there can be no practical economy, considering the 
heat-troubles from wear and tear, by using superheat at a greater 
temperature than will insure dry steam to the end of its expansion- 

work. 


152 


SUPERHEATED STEAM AND ITS WORK 


Table XXIII . —Specific Volume #f Superheated Steam in Cubic Feet per 
Pound at Temperatures Above That of Saturated Steam. 


2 6 

0) 

- 4 -> 

o3 

i i 




Specific volume for degrees of superheat, Fahrenheit. 

- 



° SR 

■2 £ 
< a 

P 

•*-> 

c5 

m 

a; J3 

03 O 
> 

20° 

40° 

60° 

00 

o 

0 

100° 

120° 

140° 

160° 

180° 

200 ° 

70 

6 

.14 

6 

.47 

6 

.64 

6 

.81 

6 

.98 

7 

15 

7.32 

7 

.49 

7 

.66 

7 

.83 

8 

.00 

80 

5 

.42 

5 

.72 

5 

88 

6 

.03 

6 

.17 

6 

32 

6.47 

6 

.62 

6 

.77 

6 

.92 

7 

.07 

90 

4 

.86 

5 

.15 

5 

28 

5 

.41 

5 

.54 

5 

67 

5.81 

5 

.94 

6 

.07 

6 

.20 

6 

.33 

100 

4 

.04 

4 

.67 

4 

79 

4 

91 

5 

.03 

5 

15 

5.27 

5 

.39 

5 

.51 

5 

.63 

5 

75 

110 

4 

.03 

4 

.29 

4 

42 

4 

51 

4 

.61 

4 

72 

4.83 

4 

.94 

5 

.05 

5 

.15 

5 

.26 

120 

3 

.71 

3 

.96 

4 

06 

4 

16 

4 

.26 

4 

36 

4.46 

4 

.56 

4 

.66 

4 

.75 

4 

85 

130 

3 

.44 

3 

.69 

3 

78 

3 

87 

3 

.96 

4 

05 

4.14 

4 

.23 

4 

.32 

4 

.41 

4 

51 

140 

3 

.21 

3 

.45 

3 

53 

3 

62 

3 

.69 

3 

79 

3.87 

3 

.96 

4 

.05 

4 

.13 

4 

20 

150 

3 

.01 

3 

.24 

3 

32 

3 

40 

3 

.48 

3 

55 

3.63 

3 

.71 

3 

.79 

3 

.87 

3 

95 

160 

2 

.83 

3 

.05 

3 

13 

3 

20 

3 

.28 

3 

36 

3.42 

3 

.50 

3 

.57 

3 

.64 

3 

72 

170 

2 

.67 

2 

.89 

2 

96 

3 

03 

3 

.10 

3 

17 

3.24 

3 

.31 

3 

.38 

3 

.45 

3 

52 

180 

2 

.53 

2 

.75 

2 

81 

2 

88 

2 

.94 

3 

01 

3.07 

3 

.14 

3 

.21 

3 

.28 

3 

34 

190 

2 

.41 

2 

.62 

2 

68 

2 

74 

2 

.80 

2 

87 

2.93 

2 

.99 

3 

.05 

3 

.12 

3 

18 

200 

2 

.29 

2 

.50 

2 

56 

2 

62 

2 

.68 

2 

74 

2.80 

2 

.86 

2 

.91 

2 

.97 

3 

03 


The above table has been computed by Schmidt’s formula based on 
Hirns’s experiments, namely: 

(17).Sv =0.59276 X- 4L p + T , 


in which Sv = specific volume in cubic feet per pound, T = temperature 
of saturated steam + superheat, P = absolute pressure in pounds per 
square inch. The percentage of increase in volume from superheat, apart 
from its freedom from condensation, is the most essential factor of econ¬ 
omy from the use of superheat; for instance, the volume of saturated 
steam at 160 pounds is 2.83 cubic feet per pound, and is increased 


by 200° F. superheat to 3.72 cubic feet per pound, and 


3.72 

2.83 


= 1.31, 


or 31 per cent, increase in volume; and at only 100° of superheat, 
which may be saved from the chimney-gases, the increase in volume 

Q QP 

i s - = 1.116, or over 11 per cent. 

2.00 


The following table represents a fair approximation to ordinary 
practice, but does not meet the extraordinary tests that have been 
published for short runs with superheat reaching near or quite to the 
temperature of incandescence. Such tests may make a good showing, 
but are not practicable for continued service. Mineral oils will not 
give the required service at temperatures above their boiling-point. 


































Table XXIV . —Estimated Steam-Consumption with Superheat of 100 °, 200 °, and 300 ° F ., for Various Pressures and Cut- 

Offs in Compound Condensing-Engines. 27-Inch Vacuum. 


SUPERHEATED STEAM AND ITS WORK 


153 


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154 


SUPERHEATED STEAM AND ITS WORK 


The superheat of from 400° to 700° F. seems practically absurd, and 
the claim of less than 10 pounds of steam per horse-power is only 
suited to an experimental test. 

The saving in steam by superheat, as shown in Table XXIV, 
say, for example, at 160 pounds, with the varying mean pressures due 

to cut-off, is, for 200° F. superheat at \ cut-off = 49 = 1-291; at \ 

1 o r>o 29 04 

cut-off 77X7 = 1.294; at 4- cut-off rrXr = 1.292, showing a uniform 
14.11 ; 6 14. 

increase of volume of 29 per cent, for various degrees of cut-off at 
200° F. superheat. At 300° F. the increase in volume is 47 per 
cent. 

Superheating should not be regarded as a means of carrying more 
heat to an engine, but only as a preventive of waste through con¬ 
densation. It has been proved by experiment that about 8 ° F. of 
superheat are required to prevent each 1 per cent, of moisture in the 
cylinder at cut-off when using saturated steam. If the specific heat 
of superheated steam at constant pressure be taken as 0.48, it follows 
that a rise of 8 ° F. in the temperature above the normal temperature 
of saturated steam of the same pressure represents the expenditure of 
0.48x8 = 3.84 thermal units. Assuming the initial condensation of 
the entering steam to be about 20 per cent., then 3.84x20 = 76.8 
thermal units which must be added in the form of superheat to in¬ 
sure dry steam at cut-off. 

The amount of fuel required to superheat steam, and the quantity 
of fuel that must be burned to continue this heat, are greater than is 
commonly supposed. It takes, as will be noticed in steam table XX, 
approximately 1,100 thermal units to convert a pound of feed-water 
at ordinary temperatures into steam at the usual temperature. By 
the addition of 76.8 thermal units in the form of superheat, we have 
increased the expenditure of heat by about 7 per cent. If all the 20 
per cent, of condensation is saved there is undoubtedly a decided 
gain; and this fact is true, that a small amount of superheat is desirable 
in all forms of engines. It is in the higher degrees of superheat that 
this difference vanishes, because the specific heat of superheated steam 
increases with the degree of superheat. 

The specific heat at constant pressure, C p , of superheated steam 
at atmospheric pressure and near the point of saturation was found by 





SUPERHEATED STEAM AND ITS WORK 


155 


Regnault to be 0.48, and until recently this value was thought to apply 
t° specific heat at higher pressures. It probably varies, as does 
the specific heat at constant volume, C v , which has been assigned a 
slightly deci easing value for superheat with increasing pressure as 
follows: 


Pressure 50 100 200 300 

C v 0.348 0.346 0.344 0.341 


for steam of moderate superheat. By recent investigations it has 
been shown that the specific heat at constant pressure, C p , is not 
constant, but that it is approximately 0.65 for 100° F. superheat, and 
0.75 for 200° F. superheat. Using these values, it can be calculated 
that the fuel used to generate saturated steam with superheat must 
be increased by the following percentages in order to superheat the 
steam to the various degrees named: 



Additional fuel needed. 

5 per cent. 


u u 


11 “ “ 

15 “ “ 


Whether, therefore, it is advisable to superheat the steam by 
direct furnace heat and increase the fuel-consumption or whether it is 
best to use saturated steam is a problem of finance rather than of 
engineering. The exception is costless superheat by the waste gases. 

Test trials by Professor Schroter, in Belgium, have shown a most 
decided economy of superheated steam as compared with saturated 
steam in the same engine, compound-condensing. 

The total cylinder-condensation when running with saturated 
steam was 9 per cent, of the total steam entering the high-pressure 
cylinder, while with superheated steam the cylinder-condensation was 
but 4\ per cent. This was at 90 pounds pressure, with superheat at 
220° F. The computed economy of superheat for steam, from an 
average of many trials, was 12 per cent., and for fuel economy an 
average of 6 per cent. 

Saturated steam on leaving the boiler carries water along with it, 
and to this is added the water of condensation in the pipes and engine- 
cylinder, amounting to 40 per cent, or more according to the plant 


150 


SUPERHEATED STEAM AND ITS WORK 


arrangement and to the type *of engine. Cylinders provided with 
jackets heated by saturated steam seldom fulfil their purpose, and 
then with but small gain; and experience has shown that at times 
jacketing is a disadvantage. Also, with saturated steam there is the 
danger of water-hammer in the cylinder and valves. This may be 
easily prevented where superheated steam is used; for in this case 
the steam is kept dry until a short time before leaving the cylinder. 
On account of the much greater volume of superheated steam, a 
smaller weight is needed to fill the cylinder, or, in other words, the same 
result is accomplished by the use of a smaller quantity of steam, and 
this in the case of a condensing-engine means that less water may 
be circulated in the condenser and consequently smaller pumps may 
be used. Although the temperature of the exhaust-steam is higher 
with superheated than with saturated steam, the smaller weight of 
superheated steam more than compensates for its high temperature, 
and thus less circulating water is necessary. 

Exhaustive comparative tests of saturated and superheated steam 
for marine purposes have recently been carried out on a steamer called 
the James C. Wallace . This vessel is one of the largest “freighters” 
on the lakes, and has lately been put into service. She is equipped 
with two Babcock & Wilcox marine water-tubular boilers with super¬ 
heaters, and the arrangement is such that the latter may be dispensed 
with and saturated steam used. The engine is of the quadruple- 
expansion, vertical direct-acting, jet-condensing type. A comparison 
based on dry coal shows a net saving in fuel, with superheated steam, 
amounting to 14.5 per cent. This result represents the combined 
increased efficiency of the machinery plant. The highest amount of 
superheat was 91° F. 

While differences of opinion may still exist aS to what type of 
superheater is the best, the patient investigation and experiments 
that have been carried on in Germany have established the fact that 
superheated steam can be used with locomotives as well as with 
stationary engines. When the much greater efficiency of superheated 
over ordinary steam is taken into consideration there seems strong 
reason to believe that the success already obtained by the stationary 
engine will be repeated with the locomotive—that materially superior 
economy in power will be attained by the use of superheated steam, 
which will in time come into general use for locomotives. 


SUPERHEATED STEAM AND ITS WORK 


157 


In Europe superheated steam is used with any type of engine, 
equipped as it may be with poppet-, slide-, piston-, or Corliss valves; 
and plants built to use saturated steam have later shown the greatest 
economy with superheated steam. Lubrication of the valves and 
cylinder is generally accomplished by means of a separate small 
oil-pump operated by the engine through a ratchet attachment. 
With compound engines a separate pump is usually provided for each 
cylinder. The oil used is a high-grade mineral oil with a very high 
flashing-point, and is extremely thick. With turbines a comparatively 
smaller pump, operated from the turbine-shaft, is used to supply oil 
to the steam-inlet and regulating mechanism. A small pump answers 
the purpose, as a turbine uses only one-sixth to one-tenth of the oil 
necessary in a reciprocating engine. The stuffing-boxes are made of 
hard metal; bronze or hard compositions and asbestos or asbestos- 
graphitic packing are much used. 

The mechanical difficulties due to the use of high-temperature 
superheat will no doubt become a bar to its extensive and continued 
use. The disintegrating effect upon the best lubricants and the un¬ 
usual friction-wear of metal and packings at high heat will eventually 
confine the superheat system to a limited or moderate temperature 
and to the more economical appliances for heat derived from the 
waste gases of the chimney—instead-of wasting the heat that should 
go to the steam in the boiler—by the use of fire-chamber devices, 
or from the losses due to furnace management in separately fired 
superheaters. 

One of the principal wastes in steam-making comes from the heat 
lost in the chimney, and any saving in this is an economical gain. 
The temperature of the chimney-gases ranges from 250 to 400 or more 
degrees Fahrenheit -above the temperature of the steam in the boiler, 
and often much higher than necessary for maintaining proper draught. 
Every thermal unit rescued from the chimney and added to the 
steam in the cylinder is a gain that costs nothing for fuel and may 
add much to the economy in the generation of steam-power, and may 
be further increased by the decreased consumption of fuel under the 
boiler. 

The saving due to the rescue of heat from the chimney may range 
from 5 to 14 per cent, of the boiler-fuel, according to the size and 
economic design of the boiler to meet its required woik. Often, 


158 


SUPERHEATED STEAM AND ITS WORK 


boilers that furnish a scant supply of steam at their limit of pressure 
may be made to meet the full requirements by the simple addition ol 
a superheating-coil in the chimney-flue. 

The value of the specific heat of superheated steam has been 
the subject of careful experiment, and by a formula from Greisman’s 
experiments the value for superheat is given, for constant pressure, as: 


(18) • 


. C p = .00222t s — .116, in which t s 


is the sum of the saturated and the superheat in degrees Fahrenheit. 
This gives for 100 pounds absolute pressure and 100° F. superheat : 
327.6 +100 = 427.6 X .00222 = .949 — .116 = .833; and for the mean spe¬ 
cific heat for both saturated and superheated steam at constant 
pr essure. A modification of Greisman’s formula, viz., 



.833 + .48 


9! 



has been proposed, which is claimed to be more nearly correct than 
by using the accepted formula, viz., 



. C p = .00222 




which for 100 pounds absolute pressure and 100° F. superheat is 


.00222 I 42 '- 6 + 327 X -. 116 = .72. 


Using this formula for the varying mean specific heat for different 
pressures and degrees of superheat, the total heat is computed by 
the formula: 


( 20 ) . 


1,091.7 + .305(t - 32) + C p (t s -1) 


by which the following table (Table XXV) of total heat has been 
computed for various temperatures of superheated steam and abso¬ 
lute pressures, using the varying values of C p , as computed from 

formula (19). For example: for 500° F. C p = .00222 +363.3\ 

-.116 = .842, and 1,091.7 + .305(363.3 - 32) + .842(500 - 363.3) = 
1,30/ .8, or 1,308, as in the table in the column under 160 and opposite 
500° in the first column. 






SUPERHEATED STEAM AND ITS WORK 


159 


Table XXV. —Total Heat of Saturated and Superheated Steam Above 
32° F., at Temperatures in Column 1, and Absolute Pressures at the 
Head of the Other Columns. 


Temp. 

Fah . 

100 

110 

120 

130 

140 

150 

160 

170 

180 

190 

200 

380 

1,217 

0 

1,214 

8 

1,212 

6 

1,210 

5 

1,208 

1,206 

1,205 

1,203 

1,201 

1,199 


390 

1,224 

4 

1,222 

2 

1,220 

0 

1,218 

0 

1,216 

1,214 

1,212 

1,210 

1,208 

1,206 

1,204 

400 

1,232 

0 

1,229 

8 

1,227 

.6 

1,225 

5 

1,223 

1,221 

1,219 

1,217 

1,215 

1,214 

1,212 

410 

1,239 

.9 

1,237 

6 

1,235 

.5 

1,233 

4 

1,231 

1,229 

1,227 

1,225 

1,223 

1,222 

1,220 

420 

1,247 

.9 

1,245 

.7 

1,243 

.5 

1,241 

4 

1,239 

1,237 

1,235 

1,233 

1,231 

1,230 

1,228 

430 

1,256 

3 

1,253 

.9 

1,251 

.8 

1,249 

7 

1,247 

1,246 

1,244 

1,242 

1,240 

1,238 

1,236 

440 

1,264 

.6 

1,262 

A 

1,260 

.3 

1,258 

2 

1,256 

1,254 

1,252 

1,250 

1,248 

1,246 

1,244 

450 

1,273 

.3 

1,271 

.2 

1,269 

.0 

1,266 

0 

1,265 

1,263 

1 262 

1,259 

1,257 

1,255 

1,253 

460 

1,282 

.3 

1,280 

.1 

1,277 

.9 

1,276 

0 

1,273 

1,271 

1,269 

1,267 

1,2~6 

1,264 

1,262 

470 

1,291 

.4 

1,289 

.3 

1,287 

.1 

1,285 

0 

1,283 

1,281 

1,279 

1,277 

1,275 

1,273 

1,271 

480 

1,300 

.8 

1,298 

.7 

1,296 

.5 

1,294 

0 

1,292 

1,290 

1,288 

1,286 

1,285 

1,283 

1,281 

490 

1,310 

.4 

1,308 

.3 

1,306 

.1 

1,304 

.0 

1,302 

1,300 

1,298 

1,296 

1,294 

1,292 

1,290 

500 

1,320 

.2 

1,318 

.1 

1,315 

.9 

1,314 

0 

1,312 

1,310 

1,308 

1,306 

1,304 

1,302 

1,300 

510 

1,330 

.2 

1,328 

.2 

1,326 

.0 

1,324 

0 

1,322 

1,320 

1,318 

1,316 

1,314 

1,312 

1,310 

520 

1,340 

.6 

1,338 

.4 

1,336 

2 

1,334 

0 

1,332 

1,330 

1,328 

1,326 

1,324 

1,322 

1,320 

530 

1,351 

.0 

1,349 

.0 

1,346 

.0 

1,345 

0 

1,342 

1,341 

1,339 

1,337 

1,334 

1,333 

1,331 

540 

1,361 

.8 

1,359 

.0 

1,357 

.0 

1,355 

.0 

1,353 

1,351 

1,349 

1,347 

1,346 

1,344 

1,342 

550 

1,372 

.9 

1,371 

.0 

1,368 

.0 

1,366 

0 

1,364 

1,362 

1,360 

1,358 

1,357 

1,355 

1,353 


S U F 

E 

R H ] 

E i 

IT E 

R 

S AND THEIR 

C O 

N S T 

R U C 

T I O 

N 


The most simple form of a superheater is a coil of ordinary steam- 
pipe, extra heavy for wear, bent into a circular shape or made up 
with return-bends, and set in the chimney-flue, or, if needed, over the 
fire in a separately fired furnace. The bent pipe-coils are much in use 
for obtaining high temperatures from superheated steam in japanning- 
ovens and in vulcanizing processes for hard-rubber goods. In this 
manner, by circulating superheated steam in pipe-coils, an oven tem¬ 
perature of 275° may be readily obtained. 

Any form of superheating-coil placed in the chimney-flues of 
boilers having ample heating-surfaces for their required output of 
steam, and in which the economy from chimney-waste has been kept 
within reasonable limits above the steam temperature, and from which 
any degree of superheat can be obtained, is a saving without cost. 

In the vast number of so-called economic types of boilers and their 
setting, a saving of 100° F. from the chimney-gases by superheat in the 
steam will make a decided saving in fuel and in boilers having large 
heat-waste from overwork; a considerable increase in power may be 




































160 


SUPERHEATED STEAM AND ITS WORK 


obtained at the first cost of a simple coil of pipe and its setting in the 
chimney-flue. 

In Fig. 126 is shown a group of tubes ready for setting in a flue or 
separate furnace; it consists of pairs of cast-iron pipes with solid 

bends, arranged as shown, and 
filled with iron-wire coils that 
produce intercirculation of the 
steam for quick-heat action by 
convection. 

In Fig. 127 is shown the 
arrangement of the heater in a 
special furnace—H. W. Bulkley 
type. Steam may be heated to 800° in these superheaters, the tem¬ 
perature of which is shown by a pyrometer in the exit-pipe. 

In Fig. 128 is shown the Metesser type of superheater-coil, which 
consists of steel tubes bent into the form shown, with their ends ex¬ 
panded into a thick steel plate with a steel or cast-iron backing divided 



Fig. 126.—Bulkley superheater. 



Fig. 127.—Bulkley superheater in brick setting. 


into two compartments. The two parts are bolted together with 
corrugated copper gaskets between the flanges. The tube-section 
may be hung in a flue-chamber or placed across the rear end of a 
water-tube boiler, in which latter case the superheater is placed in and 
securely bolted at the tube-sheet end to an iron frame, which is firmly 
anchored in the boiler-wall, while the free ends of the tubes enter a 












































































































































































SUPERHEATED STEAM AND ITS WORK 101 

lecess in the opposite wall and are prevented from sagging by supports 
placed between them. By this arrangement no joints of any kind 
are in the hot gases. 

In Fig. 129 are represented the pipe-connections for a return-bend 
superheater placed across and over the tubes of a duplex water-tube 




Fig. 128.—Metesser superheater. 




Fig. 129.—Superheater in rear 
end of boiler. 




boiler. Provision is also made for flooding the superheater with 
water from the boiler when the engine is not running. 

In Fig. 130 is shown a cluster-tube superheater set in a flue- 
chamber, in which steel tubes of suitable size, bent into U-shape, 
are flanged on, or screwed to the headers 
with right-and-left couplings in rows 
and in number of tubes to contain the 
required fire-surface. 

In Fig. 131 is shown a superheater 
made with pipe and return-bend with 
rib-flanges pushed over pipes for ex¬ 
tending the heating-surface and for pro¬ 
tection from the direct contact of the 
gases. It is placed vertically in the rear 

chamber of a horizontal tubular boiler. Fig . 130 ._ F i ue . chamber super _ 
This position of the superheater does not heater. 

























































































































































































162 


SUPERHEATED S'fEAM AND ITS WORK 

contribute to the efficiency of the boiler, although it may be an effec¬ 
tive superheater. The principle of abstracting heat that should pass 
through the tubes of the boiler is of doubtful economy. 

In Fig. 132 is shown a return-bend coil with rib-flanges placed 
in the rear fire-chamber of a marine boiler. This form is also ap¬ 
plicable to the smoke-boxes of locomotives, and in the various ways 
and designs in which it may be applied adds largely to counteracting 



Fig. 131.—Rear-chamber super¬ 
heater. 



Fig. 132.—Superheater at rear 
end of marine boiler. 


the effect of cylinder-exposure; as applied to a marine boiler the 
separate fire, with its inconvenient conditions, is avoided. 

In Fig. 133 is shown a sectional view of a separately fired super¬ 
heater and furnace. In the bridge-wall of the furnace there is an air- 
inlet for tempering the heat of the furnace before it reaches the 
superheater-coil. In this way the amount of superheat is controlled 
and overheating of coil prevented when the engine is not running. 

In Fig. 134 are shown the details of construction of the Schwoerer 
superheater, much in use in Europe. The inside ribs and outside 
flanges, cast in and on the pipe, with the method of connecting them 
with the return-bends, are shown. The tubes may be disposed either 
vertically or horizontally according to the place where they are to be 
located, and may be installed either in the uptake from the boiler, 
in the boiler-furnace, or in a setting .to be separately fired. The 
tubes are of cast iron, with transverse flanges on the outside to take 
































































































































SUPERHEATED STEAM AND ITS WORK 


103 


up heat from the gases, and longitudinal ribs on the inside to give 
up heat to the steam. These flanges and ribs are necessary on ac- 



Fig. 133.—Superheater with separate furnace. 


count of the poor conducting power of the superheated steam, which 
makes it necessary to have large surfaces for the transfer of heat. 

This cast-iron construction gives a large mass of hot metal which 
serves as a magazine for heat and acts to hold at an even tempera¬ 
ture the superheated steam which is delivered. In making joints be¬ 
tween the tubes and the connecting-bends, strong flanges are used con¬ 
nected by heavy bolts. Each flange is turned with a circular groove 



Fig. 134—Schwoerer superheater. Fig. 135.—Foster superheater. 


of triangular section, and into these grooves are placed steel rings of 
corresponding form. These steel rings, strongly compressed between 
the flanges, give an iron-to-iron joint which is sure to remain tight. 

In Fig. 135 are shown some of the details of the Foster superheater, 

























































































































































164 


SUPERHEATED STEAM AND ITS WORK 

illustrating the ends of the elements connected by a return-header. 
The elements consist of concentric, seamless, drawn-steel tubing pro¬ 
tected by cast-iron rings, shrunk on. The inner tubes are closed to the 
steam, which is thus forced through thin annular spaces and rapidly 
superheated. 

In Fig. 136 is illustrated a longitudinal section of the Babcock & 
Wilcox water-tube boiler, with the location of the superheater, and in 
Fig. 137 a cross-section of the superheater and its steam-connections. 



Fig. 136. —Longitudinal section of Babcock & Wilcox boiler and superheater. 


This superheater is not subject to the immediate action of the 
fire, as the furnace-gases must first pass through the front part of the 
boiler, which comprises a considerable heating-surface. Assuming 
the boiler to be in regular work and the firing even, no great fluctua¬ 
tions in temperature can take place where the superheater is fixed. 
Moreover, it is readily accessible for examination and for the renewal 
of tubes. 

There are no flanged joints; all the tube-joints are expanded and 
freedom for expansion is provided by the tubes being free at one end, 
and by the manifolds not being rigidly connected with each other. 

























































































































































































































SUPERHEATED STEAM AND ITS WORK 


165 



Fig. 137. —Cross-section Babcock & Wil¬ 
cox superheater. 


Prevention against overheating during steam-raising is insured 
by the arrangement for flooding with boiler-water and using the super¬ 
heater as part of the boiler heating-surface while steam is being raised 
or when it is desired to use satu¬ 
rated steam. 

As will be seen, the tubes are 
bent into a U-shape and con¬ 
nected at both ends with mani¬ 
folds, one of which receives the 
natural steam from the boiler, the 
other collecting the superheated 
steam after it has traversed the 
superheater-tubes and delivering 
it to the valve placed above the 
boiler. 

The flooding arrangement con¬ 
sists merely of a connection with 
the water-space of the boiler-drum 
and a three-way cock, by which the water enters the lower manifold 
and fills the superheater to the boiler water-level. Any steam formed 
in the superheater-tubes is returned to the boiler-drum through the 
collecting-pipe, which, when the superheater is at work, conveys 
saturated steam into the upper manifold through the heating-tubes, 
and from the lower manifold, by two tubes outside of the drum, to 
the fitting at the top of the boiler. 

In Fig. 138 is shown a section of the W. Schmidt superheater. 

The management of superheaters is of interest, and we append a 
short description of the Schmidt superheater, which is also applicable 
to other types or models. 

Superheating steam under the Schmidt system may be effected 
in one of two ways, either by placing the superheater in a chamber 
between the boilers and the main flue—this being known as the flue- 
fired superheater—and using a portion of the hot gases direct from 
the boiler-flue, or by having an independent, direct-fired superheater 
through which the saturated steam from the boiler, or battery of 
boilers, is made to pass before reaching the engine. The illustration 
(Fig. 138) represents a section of the setting and the construction 
of the apparatus. 




































































































166 


SUPERHEATED STEAM AND ITS WORK 

The saturated steam enters through the valve at the top, and, 
having been dried in the upper half of the apparatus, is led through 
suitable passages to the bottom tubes, cooling them from the inside 
and so protecting them from deterioration. It then flows in the same 
direction as the flue-gases, taking up heat from them on the way. 
The higher the temperature of the steam, the less that of the gases, 
and the steam leaves the superheater when it is hottest. The gases 

leave the superheating- 
coils at about 900° F., 
and pass on to the drying- 
coils, whence they enter 
the main flue at a tem¬ 
perature of about 460° F. 
The heat of the gases is 
thus utilized to the high¬ 
est possible extent, while 
at the same time the tubes 
are sufficiently protected 
from excessive heat. 

The superheater con¬ 
sists of a number of coils 
of equal size and dimen¬ 
sions, the ends of which 
are fixed to cast-iron 
junction-boxes. All boxes 
are placed outside the 
chamber, thus avoiding 
contact with the flue¬ 
gases, and are easily accessible even when the superheater is in service. 
Each coil can be taken out separately and a new one put in without 
removing the others or dismantling the plant. If one coil becomes 
defective, it need not be replaced at once; the ends can be stopped 
with blank flanges in a few minutes, and the tube replaced when 
convenient. 

All the water produced by condensation while the superheater is idle 
collects in the bottom junction-box and escapes through the drain-cock. 

The outside of the coils should be cleaned at intervals according 
to the nature of the fuel employed. The cleaning is effected with a 



Fig. 138.—Schmidt superheater. 











































































































SUPERHEATED STEAM AND ITS WORK 


167 


jet of steam in the usual way. A steel mercury thermometer, scaled 
to 900° F., is fitted where the superheated steam enters the main 
steam-pipe, and has a red mark to indicate the maximum tempera¬ 
ture. When this mark is passed, an electric bell rings as long as the 
maximum temperature is exceeded. A thermometer-pocket is also 
provided, in which a glass thermometer can be placed for checking 
the steel mercury thermometer. 

When starting, the superheater should be warmed with steam 
while the engine is warming up, and care should be taken to leave 
the drain-cock open until the engine has actually started. After the 
engine has run for a few minutes the cock should be closed and the 
superheater brought into operation. 

If by chance the steam should be suddenly cut off, the air-door 
underneath the lowest junction-box should be opened to enable cool 
air to enter and protect the tubes from the fire and from radiation of 
heat from the walls. This door is automatically worked by a valve 
kept closed by a weight attached to an outside lever. A chain con¬ 
nects the weight with the air-door and tends to keep it open. As 
soon as the steam begins to flow it presses the valve downward, and 
as the valve falls the weight is lifted and closes the door. 

Where an engine works continuously, and is in charge of a com¬ 
petent stoker, this apparatus is unnecessary, and can be put out of 
action by merely disconnecting the chain, but in cases of irregular 
working, and especially when the engine is liable to be stopped sud¬ 
denly without the stoker’s knowledge, the arrangement is of the 
greatest importance. 

As a general rule .the stoking of the superheater should cease 
about three-quarters of an hour before the engine is to be stopped, so 
that when the superheater is put out of action the fire will be out 
and the bricks cooled down to some extent. During this period the 
temperature gradually decreases, but the stored heat is sufficient to 
keep the steam at the required temperature until the engine stops. 

This apparatus is manufactured by the Providence Engineering 
Works. 

The conditions for enabling the use of high-pressure steam and 
high superheat with safety may be summarized as follows: 

1 . A large factor of safety. 


168 


SUPERHEATED STEAM AND ITS WORK 


2. Steam and water capacity sufficient to care for sudden fluctua¬ 
tions of load. 

3. A proper arrangement of heating-surface to thoroughly absorb 

the heat of the gases. 

4. The absence of any stayed surfaces. 

5. Straight tubes, so that they can be cleaned easily, and so that 
one can see through them and know that they are clean. 

6 . Sectional construction to insure safety and ease of repair. 

7. Wrought-steel construction throughout. 

8 . Ample surface to disengage the steam easily so as to avoid 
priming or a fluctuating water-level. 

9. Expansion.and contraction properly provided for. 

10. And last, but not least, a perfect and positive circulation of 
the water in the boiler. 

Added to the above it is imperative, on the score of economy, that 
the soot can be easily removed from the heating-surface while the 
boiler is in operation, preferably by means of air- or steam-jets. 

In Fig. 139 is illustrated a high-pressure boiler of the Babcock 
& Wilcox type with a double bend superheater coil set in the upper 



Fig. 139.—Boiler and superheater for 200 pounds pressure and 150° F. superheat. 

Babcock & Wilcox type. 




















































































































SUPERHEATED STEAM AND ITS WORK 169 

chamber with its connections to the boiler shell, arranged as before 
described. 

In conclusion, it might be well to further emphasize the advantages 
of moderate superheat of, say, 100 to 150° F. 

In most plants, if properly piped and protected, this amount of 
superheat will not only avoid condensation in the steam-mains, but 
will practically eliminate the condensation losses in the high-pressure 
cylinders of the engine, and this alone will show an actual saving, 
varying from 10 to 25 per cent, according to the class of engine and 
its condition. This, coupled to the saving effected by the use of high- 
pressure steam, and to boilers that can be cleaned and kept up to their 
efficiency while at work, is of such importance in considering the 
cost of operation that no thinking user of steam can afford to dis¬ 
regard it. 


THE M EASUKEM ENT OF STEAM- CONSUMPTION 


The quantity and value of steam sold for heating and power 
purposes to other parties, and which must be delivered through 



pipes, may be measured with fair accuracy, even when its use is vara- 
ble or intermittent. 

In Figs. 140 and 141 we illustrate the automatic recording steam- 
meter of Mr. G. C. St. John, of New York City, which makes a record 
on a chart moved by clock-work that shows the horse-power that is 

































































170 


SUPERHEATED STEAM AND ITS WORK 


being used at all times, and the aggregate per day or month. Many 
hundreds are in use in the New York steam service and throughout the 
country. The lifting of a conical valve by differential pressure allows 
the required quantity of steam to pass through the annular area, which 
is the measure under the initial pressure. The valve-lift is recorded 
on a strip of paper moved by a clock; the mean of the record-curves 
being the measure for the time. The marking-hand is moved by a 
lever from the conical valve and by a small transfer-shaft through the 
projecting hollow arm from the cylinder. The small chamber at the 
bottom is a dash-pot filled with water, which keeps the valve from 
chattering. 

The sale of steam for power and for heating purposes, in manu¬ 
facturing districts, is generally made in horse-power units, and when 
supplied to engines only, the indicated horse-power of the engine is 
the usual measure of the steam-supply, unless the waste by condensa¬ 
tion dn long pipe-lines may require an additional allowance. 

For heating purposes the unit for the price ma}^ be the same as 
for power; but the method used for obtaining the unit, when meter 
measurement is out of the question, is often a matter of controversy 
from personal differences in regard to space, and exposure of heated 
areas and their required temperature. The only reliable method 
of measurement that is available is derived from the weight of water 
drained from the heating-pipes and its weight as steam at the pressure 
in the supply-pipe. 

The horse-power in ordinary slide-valve engines varies somewhat 
from 20 pounds per horse-power hour, which may be taken as a fair 
average for indicating the amount of steam used for heating purposes. 


CHAPTER XII 


ADIABATIC EXPANSION OF STEAM 


In adiabatic expansion without loss or gain in heat from outside 
source or from the walls of a cylinder, the terms of expansion are: 


PiV l y =P 2 V 2 y ; then and ^ = /?2V 


w 

.Vs 


y-i 


Po\y=i 


Pi V 


v 2 VPp 


; also, 



y , and is also applicable to the relation of pressures 


and volumes to temperatures, and 


'VY 

,V 2y 


y-i 


T, 


= Ti and fN 


/P 2 \*=I 


y-i 


t 2 


=~; also, (— ) =^r, in which P = pres- 

ii V r / ii 


sure in pounds absolute or per square foot, V = volumes in cubic feet, 
r = ratio of volumes. T = temperatures before and after expansion. 

The ratio exponent in any equation for the adiabatic expansion 
of steam is variable as discussed by leading authorities, and as a 
sensibly perfect gas or superheated steam is given as 1.35; and 
for saturated steam varying from 1.3 to 1.111, by different authors, 
or - J y-, as adopted by Rankine for the consideration of the actual 
condition of steam behind a moving piston. Probably there is no 
exact empirical value for y for the varying influences in the make-up 
and time of expansion- in a steam-cylinder. Professor Wood gives 
the specific heat of steam at constant pressure, C p = 373.44, and for 


C Q7Q 44 

constant volume, C v = 290.16, and = ’ ■ - = 1.2869 = y for their 

P v 29u.lt) 

ratio in foot-pound values. 

Professor Zeuner found that the value of y depended upon the 
specific volume of the steam for the same initial condition at from 
1 to 4 atmospheres, and that the true value may be represented 
by the empirical formula: 

(21) . . y = 1.035 + 0.lOOx, x being derived from the formula used for 
computing Column 8, Table XXI, which is proportional for the expan¬ 
sion of steam from 160 absolute to other lower pressures. 


171 










172 


ADIABATIC EXPANSION OF STEAM 




Then for any degree of expansion between limited pressures the 
exponent y will be 1.035 +0.100x, as computed by formula (21). 

For expansion from 160 to 15 pounds absolute x may be taken 

as .865 X 0.100 = .0865 + 1.035 = 1.1215 = y , and - = .891. Then 

y 

= = 10.66 log. 1.027787X.891 =0.915758217 = index 8.237, 

\i 2/ 15 

the volume of saturated steam expanded from 160 to 15 pounds 
absolute. 

The water of condensation by the expansion of steam in this ex- 

Table XXVI. —Real Cut-Off, Corresponding to the Apparent Cut-Off, for 

Different Fractions of Clearance. 


Id 

£ o 

Real cut-off for fraction of clearance of 

' ,vj -ij 

a g 
<1 

.01 

.02 

.03 

.04 

.05 

.06 

.07 

.08 

.09 

.08 

.090 

.098 

.106 

.115 

.124 

.132 

.140 

.148 

.155 

.10 

.109 

.118 

.126 

.135 

.143 

.151 

.159 

.167 

.174 

.12 

.129 

.138 

.146 

.154 

.162 

.170 

.177 

.185 

.192 

.14 

.149 

.158 

.165 

.174 

.181 

.189 

.196 

.204 

.211 

.16 

.169 

.177 

.184 

.193 

.200 

.207 

.215 

.222 

.229 

.18 

.189 

.197 

.204 

.212 

.219 

226 

.233 

.240 

.247 

.20 

.208 

.216 

.223 

.231 

.238 

.245 

.252 

.259 

.266 

.22 

.228 

.236 

.243 

.251 

.257 

.264 

.271 

.277 

.284 

.24 

.248 

.256 

.262 

.270 

.276 

.283 

.290 

.296 

.303 

.26 

.268 

.275 

.281 

.289 

.295 

.302 

.308 

.315 

.321 

.28 

.288 

.295 

.301 

.308 

.314 

321 

.327 

.333 

.339 

.30 

.307 

.314 

.320 

.327 

.333 

340 

.346 

.352 

.358 

.32 

.327 

.334 

.340 

.346 

.352 

359 

.364 

.370 

.376 

.34 

.347 

.354 

.359 

.366 

.371 

.378 

.383 

.389 

.395 

.36 

.367 

.373 

.378 

.385 

.390 

.396 

.402 

.407 

.413 

.38 

.387 

.393 

.398 

.404 

.409 

.415 

.420 

.425 

.431 

.40 

.406 

.412 

.417 

.423 

.429 

.434 

.439 

.444 

.450 

.42 

.426 

.432 

.437 

.442 

.448 

.453 

.458 

.462 

.468 

.44 

.446 

.452 

.456 

.462 

.467 

.472 

.477 

.481 

.486 

.46 

.465 

.471 

.475 

.481 

.486 

.490 

.495 

.500 

.504 

.48 

.485 

.491 

.495 

.500 

.505 

.509 

.514 

.518 

.522 

.50 

.505 

.510 

.514 

.519 

.524 

.528 

.533 

.537 

.541 

.52 

.525 

.530 

.534 

.538 

.543 

.547 

.551 

.555 

.559 

.54 

.545 

.550 

.554 

.558 

.562 

.566 

.570 

.574 

.578 

.56 

.564 

.569 

.573 

.577 

.581 

.585 

.589 

.593 

.596 

.58 

.584 

.589 

.593 

.596 

.600 

.604 

.607 

.611 

.614 

.60 

.604 

.608 

.612 

.615 

.619 

.623 

.626 

.630 

.633 

.62 

.624 

.628 

.632 

.634 

.638 

.642 

.645 

.648 

.651 

























































ADIABATIC EXPANSION OF STEAM 


173 


ample is: 1 — .865, or 13J per cent.; and from the ratio of volumes at the 

25 85 8 237 

above pressures - * - =9.232,and- 1 —- = .111 per cent, condensation 

^.oU 9,^ow 

from the effect of expansion alone. 

In practice, the cooling effect of the cylinder-walls increases the 
percentage of condensation, which may reach 25 per cent, in slow- 
running engines. Thus the speed of piston is one of the claims for 
economy for high-speed engines. 

The values of the real cut-off in the table are derived from the 
r +c 

equation ——-> in which r = the ratio of the apparent cut-off, and c = 

the percentage of clearance. For example: for .30 cut-off with 7 per 

37 

cent, clearance, .30 + .07 = .37, and 7— = .3457, or .346, as in the table. 

1.07 

The formulas for mean forward pressure of expanding steam, as 
given by authorities who have critically investigated this subject, 
vary somewhat from the results given by the hyperbolic formula, 
which is now accepted as more nearly meeting the exact conditions 

10 9 

of steam-engine practice. Rankine’s formula Pi 


10 


seems to 


give for mean forward pressure about 2 per cent, in excess of the 
hyperbolic formula. 

In Table XXVII are given the decimal multipliers for the mean 
forward absolute pressure, with the apparent or nominal cut-off and 
clearance of from 1 to 10 per cent, of the stroke of the piston. 

For obtaining the multiplier for mean forward pressure for any 
absolute pressure, as shown in the table, from the hyperbolic formula, 
we have 


( 22 ) 


^ X 1 + c^ — c, in which R = the ratio of ex¬ 


pansion, or 


1 


—, as in Table XXVI. Then by substituting the 
real cut-off 

values for, say, .30 cut-off and 7 per cent, clearance, we have 

07 1 

XT !- = 346, and-= 2.89, the ratio R of expansion, the hyp. log. 

1.07 .346 

2.0613 


of which is 1.0613 + 1 
the table. 


2.89 


= .713X1.07 = .762-.07 = .692, as in 












174 


ADIABATIC EXPANSION OF STEAM 


Table XXVII. —Mean Forward Pressure from Absolute Initial Pressure, 
with Actual Clearance Due to the Nominal Cut-Off. 



o a 

Clearance, per cent, of stroke. 


3 2 

.01 

.02 

.03 

.04 

.05 

.06 

.07 

.08 

.09 

10 

1 0 

.10 

.344 

.357 

.369 

.381 

.392 

.402 

.413 

.423 

.432 

.441 

1 

9 

.111 

.368 

.380 

.391 

.402 

.413 

.423 

.433 

.442 

.451 

.459 

l 

8 

.125 

.397 

.403 

.418 

.429 

.439 

. 448 

.457 

.467 

.474 

.482 

l 

.143 

.432 

.442 

.452 

.460 

.470 

.479 

.488 

.495 

. 503 

.510 

1 

6 

.167 

.475 

.484 

.493 

.501 

.509 

.517 

.524 

.531 

.538 

.545 

1 

5 

.20 

.530 

.538 

.545 

.552 

.559 

. 566 

.572 

.578 

.584 

.590 

1 

4 

.25 

.603 

.609 

.615 

.621 

.626 

.631 

.637 

.641 

.646 

.650 

JL 

i n 

.30 

.666 

.671 

. 675 

.679 

.685 

.688 

.692 

.697 

.701 

. 705 

l 

3 

.333 

.704 

.708 

.712 

.716 

.719 

.722 

.726 

.731 

.734 

.737 

2 

<r 

.40 

.769 

.772 

.776 

.778 

.781 

.784 

.787 

.789 

.791 

.794 

L 

2 

.50 

.848 

.850 

.852 

.854 

.856 

.858 

.860 

.861 

.863 

.864 

5 

8 

.625 

.919 

.920 

.921 

.923 

.925 

.925 

.926 

.927 

.927 

.928 

t 

.75 

.967 

.967 

.968 

.968 

.969 

.969 

.969 

.970 

.970 

.970 


From the mean absolute forward pressure the actual back pressure 
must be subtracted for obtaining the mean effective pressure due to 
the piston-stroke. If the exhaust is directly to the atmosphere, the 
atmospheric pressure, plus the back pressure due to the friction in 
pushing the steam before the piston and through the exhaust-pipe, 
will be the total back pressure. 

The variation of the atmospheric pressure may be from 14 to 15 
pounds, according to the barometric pressure, and the back pressure 
from 1 to 3 pounds more, depending upon the frictional conditions 
in the exhaust. 

Terminal pressure is due to the stroke as 1 divided by the ratio of 
expansion, or 1 divided by the real cut-off, as found in Table XXVI, 
which gives the ratio of expansion; and for the last example 

1 _ 1 

34 ^ ~2.89, and V§t) = -346, the multiplier for the initial absolute 
pressure. 

lor example: for 100 pounds initial absolute pressure, yy cut¬ 
off with 7 per cent, clearance the mean forward pressure per Table 
XXVII is .692; the real cut-off per Table XXVI is .346, which is 
also the ratio for the terminal absolute pressure in Table XXVIII. 

Then, for example, 100X.692X.346 = 23.94, absolute, and 23.94- 
14.7 = 9.2, the terminal gauge pressure. 








































ADIABATIC EXPANSION OF STEAM 


175 


Fable XXVIII. Terminal Absolute Pressure Due to the Absolute Forward 
I ressures and Clearance, as Civen in Table XXVIT. Absolute Initial 
1 ressure X Mean Forward Pressure X Terminal Pressure Due to Cut- 
Off ^Terminal Absolute Pressure. 


d 

o 


Terminal absolute pressure for fraction of clearance of 


+-> 

p 

o 

.01 

.02 

.03 

.04 

.05 

.06 

.07 

.08 

.09 

.08 

.09 

.098 

.106 

.115 

.124 

.132 

.140 

.148 

.155 

.10 

.109 

.118 

.126 

.135 

.143 

.151 

.159 

.167 

.174 

.12 

.129 

.138 

.146 

.154 

.162 

.170 

.177 

.185 

.192 

.14 

.149 

.158 

.165 

.174 

.181 

.189 

.196 

.204 

.211 

.16 

.169 

.177 

.184 

.193 

.200 

.207 

.215 

.222 

.229 

.18 

.189 

.197 

.204 

.212 

.219 

.226 

.233 

.240 

.247 

.20 

.208 

.216 

.223 

.231 

.238 

.245 

.252 

.259 

.266 

.22 

.228 

.236 

.243 

.251 

.257 

.264 

.271 

.277 

.284 

.24 

.248 

.256 

.262 

.270 

.276 

.283 

.290 

.296 

.303 

.26 

.268 

.275 

.281 

.289 

.295 

.302 

.308 

.315 

.321 

.28 

.288 

.295 

.301 

.308 

.314 

.321 

.327 

.333 

.339 

.30 

.307 

.314 

.320 

.327 

.333 

.340 

.346 

.352 

.358 

.32 

.327 

.334 

.340 

.346 

.352 

.359 

.364 

.370 

.376 

.34 

.347 

.354 

.359 

.366 

.371 

.378 

.383 

.389 

.395 

.36 

.367 

.373 

.378 

.385 

.390 

.396 

.402 

.407 

.413 

.38 

.387 

.393 

.398 

.402 

.409 

.415 

.420 

.425 

.431 

.40 

.406 

.412 

.417 

.423 

.429 

.434 

.439 

.444 

.450 

.42 

.426 

.432 

.437 

.442 

.448 

.453 

.458 

.462 

.468 

.44 

.446 

.452 

.456 

.462 

.467 

.472 

.477 

.481 

.486 

.46 

.465 

.471 

.475 

.481 

.486 

.490 

.495 

.500 

.504 

.48 

.485 

.491 

.495 

.500 

.505 

.509 

.514 

.518 

.522 

.50 

.505 

.510 

.514 

.519 

.524 

.528 

.533 

.537 

.541 


The available heat in steam for power is essentially the sensible 
heat, that can create energy by expansion from any initial temperature 
and pressure to some lower temperature and pressure. The total 
available energy from 85 pounds gauge, 100 absolute, is: 327.6 — 212 
= 115.6° F. X 778 = 89,936 foot-pounds, or nearly 2| horse-power per 
pound of steam—less friction, condensation, radiation, and leakage— 
in any mechanical device for utilizing its energy. 

The available heat of the exhaust (latent heat) is between its 
temperature at atmospheric pressure and the temperature of the 
water after condensation, say 150° F.; then 212 —150 = 62° X778 = 
48,226 foot-pounds, or nearly 1J horse-power per pound of steam. 
Then 4} horse-power is the greatest available energy that can be 
obtained from 1 pound of steam, at 85 pounds gauge-pressure, by 
expansion and condensation. The practical operation of conversion 
is variable, and much less than the theoretical deduction. 
































176 


ADIABATIC EXPANSION OF STEAM 


Steam, when suddenly expanded, as in a cylinder, suffers condensa¬ 
tion by a small percentage, and the latent heat thus liberated is added 
to the remaining uncondensed steam. The amount, independent of 
the condensation by contact with the cylinder-walls, is shown in 
Column x, Table XXI, and by the formula from which that column 
was computed. 

When steam is compressed, as in cylinder-compression, the contrary 
effect is produced; the heat generated by compression is added to the 
steam and it becomes superheated. The economy of high-pressure 
steam has become more evident as discussion and experimentation 
have greatly advanced its possibilities during the past two decades; 
so that practically, from theoretical deduction, the total heat that is 
available for power advances with the initial pressure at a greater 
rate than the latent heat, as shown in the total latent-heat col¬ 
umns of the table of properties of saturated steam (Table XX). For 
instance, the difference at 100 pounds absolute is 298.9 heat-units, 
and at 200 pounds is 355 heat-units, or over 18 per cent, in available 
heat-units. 

The interchangeable heat effect from steam in contact with the 
surface of the cylinder-walls is made evident by the well-known 
difference in temperature of the steam at entrance and at exhaust. 
From the initial temperature during the period of admission, every 
part of the cylinder-walls in contact with the incoming steam—cylinder- 
head, piston, piston-rod, and passages—receives heat from the initial 
temperature of the steam; during which time condensation takes 
place upon their surface, and the latent heat liberated by condensation 
is absorbed by the cylinder-walls, which have become cooled by the 
lower temperature of the previous exhaust. During the period of 
expansion the temperature of the steam falls, so that at near the 
terminal it is below that of the walls that received heat by the previous 
admission, and reevaporation takes place; thus latent heat is liberated 
by transfer during admission and absorbed by reevaporation during 
expansion and the exhaust. The balance is small with high-speed 
pistons, yet in no case is there an absolute balance obtained, except 
at the expense of steam-jacket addition of heat to counteract radiation 
and air-convection. 


ADIABATIC EXPANSION OF STEAM 


-f 

\n 


ECONO M Y OF THE SIMPLE HIGH-SPEED 

ENGINE 

During the past two decades the economy of steam-engine design 
and its use of steam has been a fruitful source of discussion and ex¬ 
periment, resulting in reducing the comparative length of stroke, in 
increase of speed, and in the adoption of more perfect and automatic 
valve-motion and economic cut-off. These points are still variable 
in the designs of engine-builders, but are verging toward a uniform 
ideal. Both theory and practice now show that increased economy 
in the use of steam is found from increased pressure to certain limits 
for single-expansion, from the fact that there is more heat in higher- 
pressure steam available for doing work, in proportion to the amount 
of heat required to generate the steam, than in the case of low-pressure 
steam with its proportionate loss in doing useless work; nor is there 
any gain in extreme^ high pressure for single-cylinder engines, because 
of the loss from condensation due to the extreme range of temper¬ 
ature that would result from extreme pressures. 

In a simple non-condensing, high-speed engine the limit of economic 
pressure may be at 115 pounds gauge-pressure, and in simple con- 
densing-engines there is little advantage with steam above 90 pounds. 

In the long-stroke system, with single valves and long steam- 
passages, it is certain there is a large amount of cooling-surface that 
the steam is in contact with, while entering the cylinder, that is cooled 
by the lower temperature of the exhaust through the same passages. 

When the valves are close to the ends of the cylinder, as in Corliss 
and other types of four-valve engines, the surfaces of the ports and 
port-passages are reduced to only a trifle greater than due to the thick¬ 
ness of the cylinder-wall, which leaves only the cylinder-heads and 
piston with the small section of cylinder-wall to condense the incoming 
steam. In this type of engine there is economy. 

In the single-valve automatic engine we have a condition that, 
while simple and compact, loses a little in economy, because of the 
long steam-passages, and from the fact that the cool exhaust-steam 
must pass through the same passages and the same valve from which 
the live steam enters. With engines having the single valve there is 


178 


ADIABATIC EXPANSION OF STEAM 


not as good steam-distribution as when two or four valves are used, 
with double eccentrics. In the single-valve engines the characteristics 
are that the earlier in the stroke the steam is cut off, the greater will 
be the compression, and that at very early cut-off the compression will 
become excessive; thus we see that it is not possible to operate the 
engine with an early cut-off and realize the full benefit of expansion. 
The clearance-surfaces are, however, warmed up by the compression, 
which is a benefit in its way. 

There is no definite rule which would tell how far to carry the 
expansion in any particular case, although it is generally considered 
that the best results are obtained in the case of non-condensing engines 
when cutting off at about one-third stroke. With a simple condensing- 
engine the best results are usually obtained when cutting off at from 
one-sixth to one-fourth stroke. In compound engines varying de¬ 
grees of expansion are used, the point of cut-off in the high-pressure 
cylinder usually being adjusted to give from 12 to 20 expansions in 
both cylinders. 

When an engine is overloaded it is useless to expect to operate 
with economy, and the same will apply when the engine is too large 
to do the work, because the point of cut-off will come in one case too 
late, and in the other too early, for the economical use of steam. If 
the cut-off occurs too early there will be an increased loss from cylinder- 
condensation, and if too late, the expansion of the steam will not be 
carried out as far as it should be. It has been found that when an 
engine is running under these conditions it is better, if possible, to 
change the steam-pressure, or else the speed of the engine, so as to 
allow the cut-off to occur at a point more nearly at its correct position. 

Quoting from a series of tests which we have before us and which 
were made upon Corliss engines of medium size, we find that the amount 
of condensation and leakage, taken together up to the point of cut-off, 
was 60 per cent, of the steam consumed when the cut-off was at 5 per 
cent, of the stroke, 45 per cent, with the cut-off at 10 per cent., 35 
per cent, with the cut-off at 15 per cent., 30 per cent, with the cut-off 
at 20 per cent., 20 per cent, with the cut- off at 30 per cent., and 15 
per cent, with the cut-off at 40 per cent. 

It will be seen from the above that the percentage of loss decreases 
as the point of cut-off grows later, and the later cut-off mav cause as 


ADIABATIC EXPANSION OF STEAM 


179 


much condensation, and even more, as with an early cut-off, owing 
to the large quantity of steam used when the cut-off is late in the 
stroke. It is evident that it is better to operate an engine with too 
heavy a load than with too light a load, as far as the consumption of 
steam is concerned. 

If an engine is overloaded, the surest way of improving the opera¬ 
tion is to add a condenser, the gain of which is from 20 to 25 per 
cent., when account is taken of the steam-consumption of the engine 
only; but if measured from the coal-consumption the gain will be less, 
because it is not possible to heat the feed-water to so high a temperature 
by means of exhaust-steam when a condenser is used as when running 
non-condensing. 

STEAM-WASTE FROM LEAKAGE 

The steam-leakage past the valves and pistons of both high- and 
low-speed engines is of notable amount; at high speed the increase of 
leakage, with the greater difference of pressure on each side of the 
piston, is less than at low speed, and with jacketed, less than with 
non-jacketed cylinders. It has also been noted that good lubrica¬ 
tion of valves and cylinders reduces the leakage materially. 

In experiments made to determine what effect superheating 
would have on leakage loss, it was found, as has been the case in some 
other similar experiments, that superheating would reduce the leak¬ 
age loss about 25 per cent., the reason being, apparently, that a less 
weight of superheated steam than of saturated steam flows through 
a narrow fissure, and the condensation is reduced. 

In trials with the valve stationary there was less leakage than 
when it was moving; but when the valve was moving, the leakage 
became less as the speed of running became greater. Experiments 
made with the valve stationary in different positions seem to show 
that the leakage is approximately in inverse proportion to the amount 
of overlapping of the port and valve; that is, the greater the amount 
of overlapping the less the leakage. 

Experiments on the leakage of steam past the piston, by admitting 
ste&m to one end of the cylinder and blocking the port at the other end, 
and by weighing the condensation in the dead end, showed that this 
leak is less than 2 per cent, of the steam-consumption of the engine. 


180 


ADIABATIC EXPANSION OF STEAM 


It is evident that with a valve-leakage error of from 4 to 20 per cent, 
and a piston-leakage error of from 1 to 2 per cent., experiments on 
initial condensation which do not take these factors into account 
will be misleading. 

An unlooked-for result was the discovery that the loss due to 
condensation on the cylinder-walls of unjacketed engines diminishes 
with a rise of initial pressure and temperature, the ratio of expansion 
being constant, and that this law holds without regard to the speed 
of the engine. 


THEORETICAL EFFICIENCY OF THE 

STEAM-ENGINE 

An engine receiving all its heat at some given temperature, and 
rejecting the heat (not lost by expansion) at some lower temperature, 
must, with its conveyer, pass through a series of changes in pressure 
and volume, according to Carnot’s cycle, without loss or gain of heat 
from outside sources. Such an engine would be reversible. No such 
engine can be constructed or practically operated; but its theoretical 
efficiency serves as a standard of comparison, toward which the modern 
ideal design and construction are tending. The efficiency of the per¬ 
fect elementary engine depends only upon the highest and lowest 
temperatures between which it is worked, and is independent of the 
nature of the working substance. 

T —T 

The following table has been computed from the formula — 

in which T represents the absolute temperatures of the initial and 
exhaust steam derived from their absolute pressures. The upper 
horizontal line contain the barometric negative pressures due to the 
absolute pressure in pounds in the second horizontal line. 

A study of the above table will show approximately the saving 
that may be effected by reducing the back pressure of any engine, 
which in many cases is ignored because the effect is not readily seen. 
It has been observed, in trials, that the back pressure may be as great 
as 3 or more pounds above atmospheric pressure from the use of 
long or small exhaust-pipes, many elbows, defective valve-movement, 
or small ports or steam-passages in the cylinder. 



ADIABATIC EXPANSION OF STEAM 


181 


Table XXIX. —Theoretical Heat-Efficiency of a Perfect Steam-Engine 
at Various Absolute Initial and Back Pressures, Showing Percentage 
of Efficiency. 


0) CD 

rH 

c3 3 3 
•_2 72 ^ 

27. 

88 

25. 

85 

23.83 

21. 

78 

19. 

74 

17. 

70 

13. G3 

9.56 

5.49 

0 

+ 3 
lbs 

.3 

+ 5. 
lbs 

3 

on O 
n 0) 

M a cs 

1 

2 

3 

4 

5 

6 

8 

10 

12 

14 

7 

18 

20 

60 

25 

.3 

22 

i 

20 

.1 

18 

5 

17 

3 

16 

3 

14. 

6 

13. 

2 

12. 

0 

10. 

7 

9. 

3 

8 

6 

70 

26 

.3 

23 

i 

21 

.2 

19 

6 

18 

4 

17 

4 

15. 

7 

14. 

4 

13. 

2 

11 

•9 

10. 

5 

9 

8 

80 

27 

.2 

23 

4 

22 

.1 

20 

6 

19 

4 

18 

4 

16. 

7 

15. 

4 

14. 

2 

12. 

9 

11. 

6 

10 

9 

90 

28 

.0 

24 

8 

22 

.8 

21 

4 

20 

2 

19 

2 

17. 

6 

16. 

2 

15. 

1 

13 

8 

12. 

5 

11 

8 

100 

28 

.6 

25 

6 

23 

.6 

22 

2 

21 

0 

20 

0 

18. 

4 

17. 

1 

16. 

0 

14. 

7 

13. 

4 

12 

7 

110 

29 

.3 

26 

2 

24 

.3 

22 

8 

21 

6 

20 

7 

19. 

1 

17. 

8 

16. 

7 

15 

4 

14. 

1 

13 

4 

120 

29 

.8 

26 

8 

24 

.9 

23 

4 

22 

3 

21 

3 

19. 

7 

18. 

4 

17. 

4 

16 

1 

14 

8 

14 

1 

130 

30 

.4 

27 

4 

25 

.4 

24 

1 

23 

0 

22 

0 

20. 

4 

19. 

1 

18. 

1 

16 

8 

15. 

5 

14 

8 

140 

30 

.9 

27 

8 

26 

.0 

24 

6 

23 

5 

22 

5 

20. 

9 

19. 

6 

18. 

6 

17 

3 

16 

1 

15 

4 

150 

31 

.3 

28 

3 

26 

.4 

25 

0 

23 

9 

22 

9 

21 

3 

20. 

1 

19. 

1 

17 

8 

16 

5 

15 

9 

175" 

32 

.4 

29 

2 

27 

.6 

26 

2 

25 

1 

24 

1 

22. 

6 

21. 

4 

20. 

3 

19 

1 

17 

8 

17 

2 

200 

33 

.2 

30 

3 

28 

.6 

27 

2 

26 

0 

25 

1 

23. 

6 

22. 

4 

21. 

3 

20 

1 

18 

9 

18 

3 

225 

34 

.0 

31 

2 

29 

.4 

28 

0 

26 

9 

25 

9 

24. 

5 

23. 

3 

22. 

2 

21 

1 

19 

9 

19 

2 

250 

34 

.8 

32 

0 

30 

.1 

28 

8 

27 

7 

26 

8 

25 

4 

24. 

1 

23. 

1 

22 

0 

20 

8 

20 

1 

275 

35 

.4 

32 

6 

30 

.8 

29 

5 

28 

4 

27 

5 

26 

1 

24 

9 

23. 

8 

22 

7 

21 

5 

20 

9 

300 

35 

.9 

33 

2 

31 

.4 

30 

1 

29 

1 

28 

2 

26 

7 

25. 

6 

24. 

5 

23 

4 

22 

2 

21 

6 


For a back pressure of 3 pounds the loss in efficiency may 
be 1.3 per cent, at ordinary initial pressures, more at low pressures, 
and less at the high pressures; but when condensation and its value 
are considered, the saving is very much more apparent, and becomes 
a strong plea in favor of the use of compound condensing-engines 
wherever it is possible to operate them. Since surface-condensers 
have become so perfected and water-cooling towers available, the 
compound condensing-engine has become of the first consideration 
in the instalment of factory and electric power. 


ACTUAL EFFICIENCY 

The actual efficiency of any type of steam-engine has been usually 
derived from the number of pounds of steam used per hour, or of water 
fed to the boiler, divided by the horse-power. Thus, an ordinary 
engine, using 500 pounds of water per hour and developing 15 in¬ 
dicated horse-power, will consume = 33.3 pounds per horse-power 

I o 

hour. As a horse-power corresponds to the development of 33,000 













































182 


ADIABATIC EXPANSION OF STEAM 


foot-pounds per minute, and as 778 foot-pounds is the equivalent of 


one 


3 thermal unit, then ^—^ ==42.42 units per horse-power, which 

; 778 


may be a constant for obtaining the thermal efficiency of the engine, 

42.42 


and 


minute = thermal efficiency. 


thermal units per horse-power 
Then, for example, with a simple engine running with an initial 
pressure of 75.3 by gauge, and exhausting at atmospheric pressure, 
the formula for the thermal units per pound will be 
(28) . . xr + qi — q 2 , in which x = the percentage of moisture in the 

steam; r = the latent heat in the steam; qi = the units of heat in the 
water at the initial pressure, and q 2 = the units of heat in the water 
at atmospheric pressure or at exhaust-pressure. 

Using the values in the formula, we have: .98 X 888.4 + 291.2 —180.9 


980.9 thermal units per pound; then ^ - h - Un( ^ s = 544.4 

60 


thermal units per minute, and the thermal efficiency will be 

42.42 077 

■ = .077. 


544.4 


The best record that we have for multicompound condensing- 
engines is for about 200 thermal units per horse-power minute, which 


42.42 


shows a thermal efficiency of - 7 ^-= . 212 ; and with superheating there 


are possibilities of from 10 to 20 per cent, additional thermal efficiency 
in the use of steam and a saving of from 6 to 8 per cent, in coal-con¬ 
sumption, depending upon the method of obtaining the superheat. 


COMPRESSION AND BACK PRESSURE 

From a perusal of the large amount of discussion which has per¬ 
vaded the technical journals of late years, the economical value and 
use of compression seem to be very much tangled, although its 
mechanical value is generally conceded by the evidence of its useful¬ 
ness as shown in actual trials, in which it has been found indispensable 
in high-speed engines with a graduation due to the degree of speed. 

Its economy of steam and power seems to be the principal field of 
discussion, from which the facts should decide the points at issue. 
As its mechanical effect upon the momentum of the moving parts of 







ADIABATIC EXPANSION OF STEAM 


183 


an engine to the extent of producing its silent action at various speeds 
is obvious, it only needs the computed amount formulated from the 
experience of trials. 

The principal facts shown by the indicator-card are that the clear¬ 
ance- and steam-passages must be filled, for each stroke of the piston, 
with a volume of steam equal to the total clearance, less the exhaust- 
pressure; which adds 3 per cent, to the mean effective pressure at 
\ cut-off and 5 per cent, clearance. Then the total value of the 
clearance-volume at \ cut-off being but 3 per cent, of the mean 
effective pressure and the clearance 5 per cent, of the stroke, the loss 
of steam due to clearance will be - 3 ^= 16 per cent, loss, and 16 — 3 per 
cent, gain in power equals 13 per cent, loss due to clearance. 

On the other hand, if compression is carried up to the initial 
pressure of say 100 pounds, the heat generated by compression will 
raise the temperature of the compressed exhaust from 213° to above 
600° F., or about 260° above the temperature of the initial steam, 
the superheat of which will be given to the cylinder-walls of the cut¬ 
off and clearance-space. The back pressure due to compression will 
be fully compensated by the expansion of the accumulated pressure 
behind the piston for the next stroke, and the clearance-volume of 
initial steam will be saved. This should hold as a proportion for any 
degree of compression. 

As excessive compression is not needed for counteracting the 
momentum of the moving parts for smooth running, a noted builder 
of high-speed engines assumes that for 130 revolutions per minute, 
24-inch stroke, compression should commence at 9 per cent, from 
the terminal of the stroke; for 160 revolutions per minute, 24- inch 
stroke, 12 per cent.; and for 240 revolutions per minute, 16-inch stroke, 
19 per cent. 

The author suggests that a more equable ratio of compression for 
balancing momentum would be derived from the equation: 

(24) . „ \/ —— = length of compression in inches. 

V stroke in inches 

This may not answer fully for the difference in weight of the 
moving parts as designed by different builders and for different 
pressures. 

Of late years there has been much discussion in regard to the 




184 


ADIABATIC EXPANSION OF STEAM 


economy of compression and also as to its mechanical value. This 
discussion, and the arguments advanced for and against compression, 
have as yet proved nothing, and experiments so far made have 
shown such discordant results as to cause distrust in their methods. 

Experiments in Belgium and Germany have shown a marked falling 
off in efficiency with heavy compression, the difference amounting in 
one case to an increase of 50 per cent, in the steam-consumption. 

For instance, the experiments of Professor Dwelshauvers-Dery, at 
Liege, showed, as the compression was increased from 10 up to 30 
per cent., an increase of 21 per cent, in the steam-consumption, and 
for a further rise of 40 per cent, compression an increase of 50 per 
cent, in the steam used over that with no compression. On the other 
hand, careful experiments at Stevens Institute and at Cornell Univer¬ 
sity show only a slight change in the steam-consumption accom¬ 
panying increased compression. 

It is difficult to believe that any such difference as that shown by 
the European experiments could result from so slight a cause. The 
only loss that can result from an increase of compression is the loss of 
work shown by the rounding of the heel of the diagram, which is 
largely offset by the decrease in the amount of fresh steam required 
to fill the clearance up to the initial pressure. There is some con¬ 
densation of the cushion-steam, but this helps to warm up the cylinder 
and piston-ends and to diminish the initial condensation. 

THE ECONOMY OF HIGH-PRESSURE STEAM 

The economy due to high pressure has been slowly developed in 
practice by its gradual increase for power during the latter part of 
the nineteenth century; so that the general limit of 50 to 60 pounds 
rose to 80, 100, and even to 160 pounds for special purposes in a single 
cylinder; and for multiple expansions, 150 to 200 pounds, which is 
probably nearing its practical limit, although 250 pounds was ex¬ 
ploited many years since in single cylinders by Perkins, in England, 
with practical failure, and 1,000 pounds was used in a steam-gun of 
Perkins’s design by the author sixty years ago in New York, which 
proved a practical failure for that purpose. 

A standard boiler is assumed to evaporate 34.5 pounds of water 
per hour from and at 212° F. at atmospheric pressure, to indicate a 


ADIABATIC EXPANSION OF STEAM 


185 


boiler horse-power. This rate of evaporation is approximately used 
for the relative size of a boiler for the required consumption of steam 
per horse-power in any engine. The actual evaporation at higher 
pressures is less by a small percentage, for its rating for at 75 pounds 
pressure it is 33.85 pounds, and at 150 pounds it is 32.89 pounds. 

The weight of steam per cubic foot increases in a far greater ratio 
in a rising pressure than is due to the decrease in boiler-evaporation, 
being .0380 pound at atmospheric pressure, .208 pound at 75 pounds 
gauge, and .367 pound per cubic foot at 150 pounds gauge-pressure; 
inversely, the relative volumes vary greatly from 1,646 cubic feet per 
pound at atmospheric pressure—which is valueless as a power from 
pressure alone—to 299 cubic feet per pound at 75 pounds pressure, 
and 169 cubic feet per pound at 150 pounds pressure. 

With any given single-cylinder engine using steam at 75 pounds, 
cutting off at T 4 y with 5 per cent, clearance, the quantity of steam 
used per cubic foot of cylinder-volume will be .208 X .4 = .0832 pound 
per cubic foot, w r ith a mean effective pressure of 58.6 pounds and 
terminal of 25 pounds absolute. For the same cylinder using steam 
at 150 pounds, cutting off at yy with 5 per cent, clearance, the 
quantity of steam used per cubic foot of cylinder-volume will be 
.367X.l = .0367 pound, with a mean effective pressure of 58.8 pounds 
and terminal of 8.4 pounds absolute, thus obtaining a saving in steam 
of 56 per cent, for the same power. The saving in boiler-capacity 
and fuel will approximate this proportion. In ordinary practice these 
figures may not be reached, but a great saving has been proved under 
practical conditions. 

The losses and gains in economy of the use of steam are well illus¬ 
trated by the following diagrams. In Fig. 142 is shown the loss by 
decrease in the ratio of expansion. 

The solid outline represents the work-area due to expansion of 
steam when the cut-off occurs at half-stroke. That is, gm = 2ga, or 
the number of expansions is two. If, now, the number of expansions 
is ijncreased to three, so that gn = 3ga, then there is added an area 
bcdf , shown in dotted outline, which represents an extra amount of 
work obtained without increasing the quantity of steam used, since 
there is no alteration of the volume of steam previous to cut-off. 

For example, at 100 pounds absolute initial pressure, with 50 per 




186 


ADIABATIC EXPANSION OF STEAM 


cent, cut-off, the mean effective pressure will be 84.6 pounds for two 
expansions; if expanded three times, the mean effective pressure will be 



69.9 pounds, with 50 per cent, more work at the reduced mean effective 

pressure, or as 84.6 is to 69.9 + 34.9; then = .807, or nearly 20 

per cent, more work for the same volume of steam. 

Manifestly, then, the increase of ratio of expansion has made a 
greater amount of work available from the amount of steam used, 



Fig. 143.—Higher pressure and the vacuum. 


and it is evident that the greater the ratio the larger becomes the ad¬ 
ditional area bcdf, and consequently the less the steam-consumption 
per unit of power developed. 

The ratio of expansion may be increased by increasing the initial 
pressure and shortening the cut-off. The final volume will thus 













ADIABATIC EXPANSION OF STEAM 


187 

remain the same, but the initial volume will be less than before, and 
consequently the number of expansions will be greater. 

Fig. 143 represents an indicator-diagram from one end of a simple 
non-condensing engine. Suppose that the pressure is increased 12 
pounds, and cut-off shortened so that exhaust will occur at the same 
pressure as before. Then the steam-line will be raised to the shaded 
position and an extra amount of work will be obtained, represented 
by the area shaded with double cross-section lines. If, on the contrary, 
the initial pressure be left unchanged and a condenser added, so that 
the back pressure is reduced 12 pounds, then the area representing 


20 

18 

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■Z u 14 

P. ej 

H O* 

3 cC 12 

o W 

U M 10 

a s 

cs a 

1 « 8 

in & 

* 6 

4 

2 

> 



\ 
































\ 


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\ 
































A 




\ 

\ 































\ 





N 

N 






























\ 







V 

V 





































« s 


















































































































— 

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75 150 225 300 375 450 525 

Fig. 144.—Ideal and actual curves. 


increased work will be that shown by plain cross-sectioning. A 
comparison of the two areas, which are to the same scales, makes 
plain the gain to be derived from reducing the back pressure in a 
non-condensing engine, rather than by increasing the initial pressure. 

To illustrate further the economy of the use of steam at high 
pressure, the diagram (Fig. 144) shows the relation of the ideal and 
actual curves with the steam-consumption at varying pressures in 
condensing-engines. 

The curve shown solid is for the ideal engine, and consequently 
is practically valueless, inasmuch as it does not pertain to actual 
results obtained. But it does show what the perfect engine might 
accomplish, and it thus forms a basis of comparison for results 
































































188 


ADIABATIC EXPANSION OF STEAM 


which have been secured in practice. The curve shown dotted is 
plotted from the results of tests made upon actual engines at various 
steam-pressures, the results showing highest economy being taken 
in plotting the curve. As can be seen, the actual curve approaches 
the ideal as the pressure rises, indicating that as the pressure is in¬ 
creased the economy of the actual engine approaches more nearly 
that of the ideal engine. 

THE MOST ECONOMICAL POINT OF CUT-OFF 

This was a much-discussed question a few years since, and the 
cut-off was claimed to be equal to the 

absolute back pressure 
absolute initial pressure 7 

but as nothing was proposed in regard to the effect of the clearance 
in this formula it should be added to give the real cut-off. For ex- 



0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00 

Cut-off in Fractions of Stroke 


Fig. 145.— Diagram of economical cut-off. 


ample, an initial pressure of 90 pounds and terminal pressure of 1 

15 7 

pound by gauge; this would be —f— =.15 cut-off, which would give 

104.7 


a mean engine-pressure of 44 pounds without clearance, and 52 pounds 
with 10 per cent, clearance, with a corresponding increase of steam 
equal to a 20-per-cent, cut-off without clearance. 




























































ADIABATIC EXPANSION OF STEAM 


189 


The experiments of Professor Denton show a larger cut-off for 
the above conditions by a possible addition of the clearance to the 
theoretical cut-off as above given. 

In Fig. 145 is a diagram of the curves showing the most eco¬ 
nomical cut-off at different pressures and the consumption of steam 
corresponding with the cut-off. The engine was a 17 X 30-inch non¬ 
condensing, double-valve type, with clearance stated to be large. 

In the diagram the vertical lines represent the cut-off, and the 
horizontal lines the pounds of steam consumed per effective horse¬ 
power. The intersection of the curves with the vertical lines shows 
the variation of the weight of steam for each advance in the point of 
cut-off. It will be seen from tracing the curves that the best result 
for 30 pounds pressure was obtained at about T 4 yV cut-off, that for 
60 pounds at about cut-off, and that for 90 pounds at about 
y 2 -^- cut-off. For a short distance each side of these points of cut¬ 
off the economy shows but little variation, and that with increasing 
pressure the point of economical cut-off has an inverse decreasing ratio. 

From these and other experiments a formula has been deduced 
for approximately the most economical cut-off for a non-condensing 


simple engine, in which the cut-off = 


100 

42 4/P’ 


in which P is the initial 


gauge-pressure, or above the atmospheric, and above a vacuum for a 
condensing-engine. 

The cut-off in a single-cylinder engine is limited, by an initial 
gauge-pressure of about 110 pounds with 5 per cent, clearance, to a 
minimum of one-fifth of the stroke for economic effect, as in this case 
the terminal pressure will be but 1 pound above atmospheric and will 
about equalize engine-friction. 




CHATTER XIII 


THE INDICATOR AND ITS WORK 


The means of knowing what are the steam conditions within the 
cylinder of an engine is a most important one to all concerned in the 
operation of steam-power. 

The interpreter is found in the indicator, a recorder of the varying 
pressures within the cylinder from which the action of the valves 
and valve-gear is noted upon sight, and by means of which the value 
of the steam used is made a matter of rapid computation. 

The indicators in use are of several patterns, all made on the 
same general principle, namely, a light-moving piston, pressed by the 

steam against a delicate 
and accurately gauged 
spring, operating a light 
parallel-motion device, 
which marks the lines 
of pressure by a pencil 
on a paper moved too 
and fro, and which is 
placed upon a cylinder 
and actuated by the 
motion of the pis¬ 
ton within the engine- 
cvlinder. 

In Fig. 146 we illus- 



Fig. 146.—Indicator and reducing-wheel. trate one of the latest 

patterns of an indicator 

having a light aluminum reducing-wheel attached directly to the 

diagram-drum. The reducing-wheel has a number of bushings for 

its upper section, of sizes to equalize the length of diagram or card to 

any length of piston-stroke. This method of reducing the piston- 
190 



































































































































































the indicator and its work 


191 

stroke ol the engine is so neat; complete, and accurate that we forego 
illustration of the many awkward reduction-devices in use. 

In Fig. 147 are shown the details of the construction of the Lip- 
pincott indicator. It 

will be noted that 
the indicator-cylinder 
is steam-jacketed, with 
steam-inlets below the 
piston so that the cylin¬ 
der and piston temper¬ 
atures are always the 
same and are also un¬ 
der the same pressure 
—a great advantage 
when indicating under 
high pressures. 

A special feature in 
its construction is the 
free-moving piston, 
which has a guide-rod 
to which it is fixed, 
with bearings at the 
top of the spring and 
in the cylinder beneath the piston, giving a perfect and free lineal 

motion to the piston and being practically 
frictionless. The piston-area is usually exactly 
J inch for use up to 100 pounds pressure, with 
springs of 60, 50, and 40 pounds per inch of 
height in the card, while the high-pressure piston- 
area is exactly J inch, and is suitable for indi¬ 
cating up to 200 pounds pressure with the No. 
60 spring. 



Fig. 147.—Lippincott indicator. 



Fig. 148.—High-press¬ 
ure piston. 


THE ALUMINUM REDUCING -WHEEL 

It is unnecessary to go into the relative merits 
of the reducing-wheel versus the pendulum, 
lazy-tongs, pantagraph, etc., as the superiority 














































































































































































































































192 


THE INDICATOR AND ITS WORK 


of a good wheel over these antiquated devices is conceded by all 
up-to-date engineers. We admit that some reducing-wheels give so 
much trouble from disarrangement of cords, breakage of springs, 
and excessive wear that some engineers have gone back to the 
old methods; but we have yet to learn of a case where a user of 
the aluminum wheel has discarded it. By the aid of this wheel 
directly connected to the indicator it is possible to indicate several 
different engines in a day; but we have known of hours being con¬ 
sumed in securing material for, and rigging up, a pendulum, and often 
with inaccurate results. 

The general design of the wheel is shown in Fig. 146. It is com¬ 
pact, and at the same time has not been made so small that it is 
subjected to rapid wear by use, or so that its application to long- 

stroke engines will seriously tax 
its capacity. 

The main-cord wheel is made 
of aluminum, turned inside and 
out, and perfectly balanced. This 
wheel is capable of operating on 
strokes as high as 7 \ feet, or more, 
but by substituting a smaller pul¬ 
ley it becomes suitable for short 
strokes and high speeds, its range 
then being from 6 to 24 inches. 

The spring-case spindle ex¬ 
tends through the case, and is 
provided with a coarse square thread, eight to the inch, upon which is 
a suitably shaped composition-nut, to which is attached the guide- 
pulley arm. 

Each revolution of the main-cord wheel moves the guide-pulley 
across the face of the wheel about T y inch, so that the main cord is 
guided perfectly on the wheel, no matter in what direction it is led. 

The setting of an indicator is an important matter when accurate 
results are sought. The point most desired is to have a quick transit 
of the pressure in the cylinder to the piston of the indicator, and 
for this purpose the indicator should be attached directly to the 
clearance-space, of the cylinder without piping, elbows, or cocks. 



Fig. 149.—Close-connected indicators. 

























































THE INDICATOR AND ITS WORK 


193 



save the one on the indicator. This is most desirable on high-speed 
engines, as shown in Fig. 149; but as this needs two indicators, the 
usual way for a single indicator is to connect the clearance-spaces with a 
cross-pipe, with the indi¬ 
cator in the centre, as 
shown in Fig. 150. When 
the connecting-pipes are 
desired to be retained, 
the angle-cocks at each 
end are needed to lessen 
the clearance. In this 
case, with long-stroke 
engines the cross-pipe 
should be one size larger 
than the thread of the 
indicator-cock ; but a 
better way is to use two 
indicators. 

A too long pipe-con¬ 
nection or a too small one produces freak cards, which do not represent 
the true action of the steam within the cylinder. On Corliss and other 

four-valve engines the in¬ 
dicator is attached at the 
side of the cylinder, as 
shown in Fig. 151. In 
connections to vertical 
cylinders care should be 
had to prevent water from 
filling the indicator-con¬ 
nection, as it tends to pro¬ 
duce a freak card for the 
lower end of the cylinder. 

When a pendulum or 
pantagraph reclucing-gear 
is employed a light and 
very flexible spring may 


Fig. 150.—Cross-pipe connection. 



be used to advantage to keep the cord uniformly taut. An arrange 
ment of this kind is shown in Fig. 152, in which a loop or hook 

































































































































194 


THE INDICATOR AND ITS WORK 


attached to the cord may be extended by a light cord to a spring at 
the side of the cylinder or engine-frame—a needed arrangement for 
high-speed engines. 



Indicators are made right-and-left-hand, or with adjusting parts 
to make the same instrument set both ways, as will be seen in Fig. 

153, in which the pencil- 



holder may take the pen¬ 
cil in opposite directions, 
the stop-screw being 
changed from one to the 
other side of the arm, 
and the drum shifted to 
notches provided for the 


change. 


The details for oper¬ 
ating the various makes 
of indicators are sent 
with the indicators, and 
much of their mechanism 
becomes apparent to 
engineers on inspection. 
The pencil should be 
hard and sharp and the paper hard, cold-pressed letter-sheet or 
bond-paper, which gives a good marking with the lightest pressure 
of the pencil-arm. 























































THE INDICATOR AND ITS WORK 


195 


* MEASUREMENT OF THE INDICATOR-CARD 

The method of measuring the mean engine-pressure from the in¬ 
dicator-diagram is shown in the double card (Fig. 154), which is the 
usual way for taking the card for both forward and back strokes. To 
lay off the diagram for measurement, run off on the straight edge of 
a piece of paper with a dividers, eleven spaces that will overrun the 
length of the diagram. Draw vertical lines at both ends of the diagram 
and two lines below it, parallel with the atmospheric line, for a register 
of the measurement. Lay the scale diagonally across the diagram, 
as shown in the illustration, at an angle that will just divide the end- 
spaces over the vertical lines at each end of the diagram; then mark 



with a point or pencil on the diagram the ten divisions on the scale, 
and draw vertical lines across the marks, continuing them over the 
outside register-spaces. Then proceed to measure, with the scale 
corresponding with the indicator-spring, between the steam- and ex¬ 
pansion-lines and the exhaust line and compression line. Enter the 
amounts under the heads H and C in the columns below. Divide 
their sums by 10 for the mean forward pressure of head- and crank- 
ends, and equalize for their combined mean forward pressure, less the 
back pressure; from which the horse-power may be computed, and 
from the established point of cut-off the steam-consumption may be 
found, as described in previous sections of this work. See “Com¬ 
pression” and “Steam Used per Horse-Power.” 




































196 


THE INDICATOR AND ITS WORK 


THE PLANIMETER AND THE MEASUREMENT O ^ 

THE INDICATOR-DIAGRAM 

The most perfect measurement of the area and mean pressure of 
an indicator-diagram may now lie made by the use of the planimeter 
which has been perfected in all its details. 

In Fig. 155 is shown the Amsler planimeter, which consists of 
two legs jointed with points at their ends, one of which is fixed, and 

the other, the tracer, is moved 
over the diagram in the same 
direction as the indicator- 
pencil. 'At their juncture is a 
small shaft with a sharp-edged 
disk, a cylindrical section with 
a graduated scale read from a 
fixed vernier scale. A worm- 
screw and index-wheel indi¬ 
cate the number of revolutions of the rolling disk. To operate this pla¬ 
nimeter, set the stationary point at any position, so that the tracing- 
point can be carried around the line of the diagram without bringing 
the wheel in contact with the paper on which the diagram is traced— 
preferably so that the leg with the tracer in moving around the dia¬ 
gram will cover an angular space 
between 30 and 90 degrees from 
the stationary pointer-leg. 

For the mean effective pressure 
divide the area as indicated by the 
scale by the length of the diagram 
in inches , and multiply the quotient 

by the scale oj the spring used in Fl0 . 156 ._ Lippincott p i animeter . 
the indicator. 

One of the models of the Lippincott planimeter is shown in Fig. 
156, in which R is the stationary point; T the tracer; c a smooth, 
round arm on which a scale is laid off; D a disk with a free motion on 
the scaled arm. The traverse of the wheel on the scale indicates 
the area. 

In F ig. 157 is shown the Lippincott simplex planimeter in position 









107 


THE INDICATOR AND ITS WORK 


for tracing the area of an indicator-diagram. This model eliminates 
any possible error due to the looseness of the traversing-wheel in Fig. 
15(5, inasmuch as the wheel is fixed on a small shaft which travels 
under roller-bearings at either end of the frame; so that the plane of 

the wheel is ligidly at right angles to its axis and therefore registers 
without error. 

To use the simplex planimeter a large sheet of smooth cardboard 


should be obtained and the instrument placed on the diagram, about 
as shown in the figure, with the tracer-point B at either of the points 



Fig. 157.—Simplex planimeter. 


X, and the wheel TV about f inch from the body of the instrument 
(this distance is not important, only that the wheel must not strike 
the frame at either extreme of its travel). The position of the pivot- 
point F should be particularly noticed, the angle of the arm being 
somewhat greater than a right angle. 

While the planimeter is held in the position shown in the figure, a 
slight pressure on the wheel TV makes an indentation in the paper 
which is easily seen. The diagram is then traced in the direction of 
the arrows, until the tracing-point returns to the starting-point X, 
and while in this position the wheel W is again pressed in the paper, 
thereby leaving two indentations. The distance between these, 
measured by a scale of the same dimensions as that of the indicator¬ 
spring—a 60 scale for a 60 spring—gives the mean effective pressure 
direct and accurately. For the mean effective pressure direct, the 














THE INDICATOR AND ITS WORK 



198 

tracer-bar should be extended until the points A and B are the same 
distance apart as the extreme length of the diagram. If the reading 

is desired in square inches 
and tenths, the points 
A and B should be set 
6 inches apart and a 60 
scale used for reading the 
area in square inches and 
tenths. 

The three positions of 
the planimeter, shown in 
Fig. 158, are those as¬ 
sumed during the tracing 
of the diagram. 

No attention need be 
given to the movement of 
the wheel while the card 
is being traced, except 
that the wheel is clear 
from the frame by f inch 
at the start, B, and does 
not run against the other 
end of the frame at the 
finish, D, by an extra large 
diagram. As the wheel 
rolls—when the motion is 
parallel to the tracer-bar 
—and as the shaft slides 
under the roller-bearings 
without friction for all 
movements at right an¬ 
gles to the tracer-bar, 
there is no scraping on the 
paper, so that the line 
may be traced without varying resistance, and the personal error 
due to the operator is materially reduced. 





















































THE INDICATOR AND ITS WORK 


199 


WATER USED PER HORSE-POWER HOUR 

The indicator-card, besides giving the horse-power at which the 
engine was working when the card was taken, and the adjustments 
of valves, also indicates how much water the engine is using per hour. 
This amount is usually then reduced to the amount of water required 
by the engine per horse-power per hour, so that it can be compared to 
other engines, as each engine runs under varying conditions and may 
be of a different type. This unit is taken as a standard of comparison. 

The indicator-card assumes that all the steam within the cylinder 
is steam, and takes no account of initial condensation or condensation 
during expansion. It also does not take into account any leakage, 
either through the valves or past the piston. The only way that 
the actual amount of water that an engine uses can be obtained is 
by direct measurement. This is done either by condensing the steam 
after it has passed through the cylinder, and weighing it, or by weigh¬ 
ing the water before it enters the boilers on its way to the engine. 
However, indicator-cards must be taken, from which the horse¬ 
power is obtained, and as the amount of water that the engine uses 
in one hour can be measured, by dividing that quantity by the horse¬ 
power the real amount of water that the engine uses per horse-power 
per hour can be obtained. This is usually a very laborious and 
painstaking process, and the necessary appliances and apparatus are 
rarely at the disposal of the engineer. 

It is for this reason that the indicator-cards are used for this 
purpose, giving as they do an indication of the amount of water 
used by the engine, and therefore the economy. An engine always 
uses more water than that represented by the indicator-diagram, 
but never uses less water than that shown by the diagram, so that 
if the diagram shows an uneconomical consumption, the engine is 
sure to be uneconomical; but if the indicator-card shows that it is 
economical, it may or may not be true. This latter condition depends 
upon whether there is much initial condensation or much leakage. 
The more leakage and initial condensation, the more will the theo¬ 
retical amount differ from the actual amount. There are always 
some leakage and initial condensation present in every engine, and it 
is for this reason that an indicator-card represents the least amount of 
water that the engine can use. 


200 


THE INDICATOR AND ITS WORK 


The method for finding this amount is explained as follows: The 
clearance-space of the engine should be known. By clearance in 
this case is not meant the mechanical clearance between the head of 
the cylinder and the piston when the latter is at the end of the 
stroke, but the volume of steam that is required to fill the valve- 
passages plus this mechanical clearance. 

The data that should be known about the card are its length, the 
scale of the indicator-spring with which it was drawn, and the horse¬ 
power, which can be obtained from the area of the card by the usual 
formula: 

TJ PLAN 

Horse-power^——, 

where P = mean effective pressure in square inches; A = area of cylinder 
in square inches; L = length of stroke in feet; N = number of strokes 
per minute. 

The mean effective pressure is obtained by multiplying the area 
of the card by the scale of the spring and dividing the product by 
the length of the card; 


area of the card 
length of the card 


X scale of the spring. 


The most accurate method of procedure is to assume some point 
on the expansion-line of the card, as at A (Fig. 159), and find the 
pressure that corresponds to it. The line Am represents the position 
of the piston at the point A. As no more steam can enter the cylinder 
from the boiler after cut-off, any point can be taken on the expansion- 
curve after cut-off. The percentage of clearance being known, the line 
OG is erected at a distance from the admission-line equal to that 
percentage of the length of the card. That is, if the clearance is 3^- 
per cent., the distance C is 3^ per cent, of the distance L. Next find 
the pressure of the steam at point A. This is obtained by measuring 
the height Am, and multiplying it by the scale of the spring. 

Assuming for the diagram an initial gauge-pressure of 145 pounds, 
card = 4.08 inches in length, exhausting on or near the atmospheric line; 

75 

x = .75 inch, and = .183 cut-off. Gauge-pressure at A = 120 pounds; 

gauge-pressure at B, 60 pounds; and the mean effective pressure is 
found, as before described, to be 41 pounds per square inch. Then 





THE INDICATOR AND ITS WORK 


201 


for 1 cubic foot of steam in the cylinder, the weight at 120 pounds 
gauge by the steam-table is .304 pound. As the proportion of a cubic 

foot contained in the rectangle xAm is A~ = . 183 percent, of a cubic 

4.08 

foot, then .304 X. 183 = .05563 pound, and ~ 563 X60 X 33,000 = 

41x144 

pounds per horse-power hour. Also: ~~= 13,750, a constant, 

144 ' ’ 

„ , .05563X13,750 

ana ^-=18.656 pounds per horse-power hour, as before. 


Then for any size cylinder under these conditions, its volume in 
cubic feet multiplied by the speed of the piston in feet per minute— 
by 60 and by .05563—will equal the total weight of steam consumed 
per hour. 

For the additional steam required to fill the clearance between 
the volume due to compression and that due to the initial pressure, 



we find for 145 pounds initial pressure .356 pound per cubic foot, and 
for 60 pounds, .175. Then .356 — .175 = .181X.035 (clearance) = 
.0063 + 18.656 = 18.662 pounds, the total weight of steam required per 
horse-power hour. With compressions running nearly up to the initial 
pressure, the differential loss is of inconsiderable value; but with no 
compression the loss would be .356X.035 = .01246, or, say, 1| per cent. 


















202 


THE INDICATOR AND ITS WORK 


With considerable compression, and with the exhaust-line above the 
atmospheric line, as shown in the diagram, the computed compression 
may be largely increased and carried up to the initial pressure; and, 
inversely, when the exhaust-line is below the atmospheric line, the 
assumed compression is lessened. 

An indicator-card from an automatic slide-valve engine, with 
cut-off .115, and exhausting at 2\ pounds back pressure, is shown in 
Fig. 160. This engine had a 12 by 18 inch cylinder; revolutions, 124; 
boiler-pressure, 68 pounds; initial engine pressure, 65 pounds; com¬ 



pression, 57 pounds; estimated mean effective pressure, 25.5 pounds; 
computed horse-power, 32.5. Neglecting the clearance, which is 
nearly compensated by the excessive compression, and including the 
loss by the steam wasted in the back pressure, we find the pressure 
at A, from the atmospheric line, 32 pounds, at which pressure 1 cubic 
foot of steam weighs .113 pound. 

112 

Then x = —— = .3093 X. 113 = .03495 pound, the weight of steam 

o.DiJ 

used per cubic foot of cylinder-volume, and, using the formula, 
W 13,750 

jjj.—^—p- = pounds per horse-power hour. 


Hence 


.03495 X 13,750 
25.5 


18.8 pounds of steam per horse-power hour. 


Then for the total steam-consumption, 18.8x32.5 = 611 pounds 
per hour. With a loss of 15 per cent, by condensation during ad- 

18 8 

mission, then — ~ .=22.1 pounds per horse-power hour, or a total of 


718 pounds per hour. 











THE INDICATOR AND ITS WORK 


203 


INDICATOR -KINKS AND ADMISSION AND 

TERMINAL LINES 

The distortions of the lines of the indicator-card are frequently 
made a cause of inquiry by engineers, and for their better understand¬ 
ing we illustrate some of these kinks-, with their accounting. 

Fig. 161 is a fairly good card showing a small advance of the cut¬ 
off at the head-end over that at the crank-end, which also shows its 
effect on the exhaust-end by the fuller curve. The cut-off of .37 at 
the head-end and .34 at the crank-end shows this effect. It is not the 
most economical power-card, as the exhaust commences at 40 pounds 
and would make a better showing of steam-economy at one-fourth to 
three-tenths cut-off; but with an automatic cut-off these are neces¬ 



sarily variable points. The compression is one-half the initial pres¬ 
sure, or 64 pounds, which should make a smooth-running engine at 
the speed shown on the card. 

The wavy expansion-lines often shown on indicator-cards are 
mainly due to friction in indicator parts, such as a sticky or too tight 
piston, looseness or tightness of the joints, too much pressure of the 
pencil upon the paper, rough paper, irregular tension of the barrel¬ 
spring by touching the sides of its chamber, elasticity or vibration 
of the cord, and the momentum of the moving parts—the last of 
which is greatly increased with high speed. All these produce irregu- 







204 


THE INDICATOR AND ITS WORK 


lari l ies not due t o valve-motion, but may sometimes become acccn 
tuated by leaky valves. 


The admission- and release-lines as shown on 


indicator-cards, 



have distinct bearings on the action of the indicator, the valves, 
and the steam in the cylinder. 

The diagram A Fig. 163 shows that at the moment when the com¬ 
pression-line C is completed the valve opens quickly and throws the 
admission-line vertically to the initial pressure. This involves the 
question of lead, the amount of which the size of the engine and the 
speed may determine. Lead should be as little as possible and allow 



Fig. 163.—Compression- and admission-lines. 


the admission to be vertical. When lead is made to admit steam 
just before the end of the stroke, the compression-line is carried up¬ 
ward, as at B. This has been a matter of discussion; but the con¬ 
sensus of opinion is that compression should be high with small lead, 
especially with high-speed engines. D and E show that the valves 
opened late—so much so in E as to invalidate the value of the card 
for economy. 

The point X above the admission-line Y in the diagram F may 





















THE INDICATOR AND ITS WORK 


205 


indicate too quick opening by lead and the momentum of the moving 
parts ol the indicator from the sudden pressure—more often made by 
high-speed engines. 

The steam-lines, Fig. 164, indicate variations in the normal action 
of valves, in which G shows a full opening to the boiler-pressure dur¬ 
ing admission, H a too small steam-pipe or excessive speed, I 



K 


Fig. 164.—Steam-lines. 


probably a large steam-chest and small steam-pipe, and J a light 
load and early cut-off. K shows slight compression and steam ad¬ 
mission just past the centre—a good indication for a pounding engine. 

The line L in Fig. 165 has the compression-line rising to the point C 
and forming a small loop, caused by late admission, the valve not 
opening until the return-stroke is well under way. 

The diagram M shows a still later opening of the valve sometimes 
met with, in which the loop may vary in size and be carried to the 



Fig. 165.—Erratic admission-lines. 


top of the card, as in the diagram N, when the compression-line extends 
above the steam-pressure in high-speed engines from over-compres¬ 
sion and late valve-opening. The same effect is shown in diagram 0 
for light load and short cut-off. An offset in the compression-line, 











206 


THE INDICATOR AND ITS WORK 


as 0 at P, indicates a leak during compression by a valve lifting 
from its seat—generally the exhaust-valve in four-valve engines. 

The diagram Q Fig. 166 shows that the exhaust closes too late 
to cause any compression, the piston starting on its return just be¬ 
fore the inlet-valve opens, when steam may 
blow through the exhaust-valve. 

In the diagram R the exhaust-valve does 
not close until the piston is well on its way, 
causing a slight vacuum before the inlet- 
valve opens, owing to slipping of the eccen¬ 
tric, thereby making the whole valve-motion 
late. 

The forms of the release-lines are relative 
counterparts of the steam- and admission¬ 
lines, and are subject to abnormal proportions depending upon the 
steam-lines and the exhaust-valve action. 

In the diagram B Fig. 167 the dropping of the expansion-line 
below the exhaust is very undesirable in a working engine, except 
in extreme conditions of load or in friction trials. The loop B varies 



Fig. 167.—Release-lines. 


in form and length by the action of the exhaust-valve. In the diagram 
C the release takes place at D by too early opening and throttling 
of the exhaust-valve, whereas the opening should be made at E, as 
shown by the dotted line, and a small saving made in the mean 
effective pressure. A better release is shown at F and H. There can 
be no object in delaying the release causing increase of pressure at the 
moment of exhaust, as shown at G and J, the latter being a late release 
on a condensing-engine, of which K is a good example of a slow release. 
The small drop near the end of the expansion-line generally shows a 


r 



Fig. 166.—Faulty valve¬ 
setting. 


















THE INDICATOR AND ITS WORK 207 

slow action of the exhaust-valve, or a throttling in the exhaust- 
passages. 

In Fig. 168 are shown two sets of cards from a high-pressure 
cylinder—30x48—at 87 revolutions per minute, exhausting into a 



Fig. 168.—-Exhaust-lines. 


receiver under a varying load. The sweeping upward of the exhaust- 
line through the middle of the stroke shows a throttling of the exhaust- 
passages between the high-pressure cylinder and the receiver. 

Much more might be written in regard to the eccentricities ob¬ 
served on indicator cards, due to the combined effects of valve-gear 
setting and its looseness of joints; irregularities of indicator move¬ 
ments and transmission devices; but we think enough has been 
shown to cover the leading faults, from which the origin of minor 
irregularities shown on cards may be readily located. 



















CHAPTER XIV 


STEAM-ENGINE PROPORTIONS 

Economy in the use of steam is one of the first considerations in 
the design of a steam-engine. The cylinder, its principal part, should 
have its relative dimensions of diameter and stroke as nearly equalized 
as possible, unless other requirements—such as speed, or lightness 
of parts, or of the whole engine—suitable for its special service, may 
be inducements for designing the longer stroke and slower speed, as 
used in the comparatively slow-speed Corliss type. A large propor¬ 
tion of the high-speed engines of to-day are designed on the short- 
stroke ideal. 

The considerations for the condition of the steam are essential, 
and may be taken as follows: 

Saturated steam is steam of the temperature due to its pressure. 

Superheated steam is steam heated to a temperature above that 
due to its pressure. 

Dr}/ steam is steam which contains no moisture, and it may be 
either saturated or superheated. 

Wet steam is steam containing intermingled moisture, mist, or 
spray, with a temperature equal to that of dry saturated steam at 
the same pressure. 

The following formulas for steam-engine proportions are quoted 
from various authorities, and show slight differences derived, probably, 
from different lines of investigation and experience in formulating 
values for steam-engine design. The builders of to-day may have 
arrived at still different values and proportions in their practice. 

Initial Condensation. 

g pp_.f\ 

Bodmer: W = weight of steam condensed = C- 5 -=- pounds per 

minute. WN* 

T =mean admission-temperature; 
t =mean exhaust-temperature; 



STEAM-ENGINE PROPORTIONS 


209 


S = clearance-surface in square feet; 

N = number of revolutions per second; 

L = latent heat of steam at mean admission-temperature; 

C = constant for any given type of engine. 

For high-pressure, non-jacketed engines, C = about .11; for con¬ 
densing, non-jacketed engines, C= .085 to .11; for condensing jacketed 
engines, C = .085 to .053. The figures for jacketed engines apply to 
those jacketed in the usual way, and not at the ends. 

C varies for different engines of the same class, but is practically 
constant for any given engine. 

The condensation may be, under varying conditions, from 20 to 
50 per cent, of the weight of steam given to the engine. 


The Cylinder—Diameter. 

Bodmer: P = mean effective pressure in pounds per square inch; 
L = length of stroke in feet; 

A =area of piston in square inches; 

N = number of strokes per minute; 
r = ratio of length of stroke in inches to the distance 
travelled by piston in inches before cut-off; 
px = initial pressure in pounds per square inch; 
p 2 = absolute boiler - pressure = gauge reading +15 
pounds. 

If pipe from boiler is well lagged: 

pi =i-f P 2 (Whitham); 

p _l+hyp.l°g.r pi _ bac k pressure; 


I. H. P.x33,000 . 

A " PLN 

Diameter = D = 2 A=205 
Thurston gives DL to L. 

For compound engines design the low-pressure cylinder by the 
same formulas used in designing a single-cylinder engine, for the total 
power, given initial and exhaust pressures, and total expansion. The 
size of the high-pressure cylinder is then determined by the table of 
cylinder-ratios. 







STEAM-ENGINE PROPORTIONS 


210 


Cylinder-Ratios in Compound Engines. 


Grashof: 
Hrabak: 
Werner: 
Rankine: 


Busley: 


V 


= .85/ 


r. 


— = . 94 / r. 

Y 


'V /— 

— = V 1 -. 

v 


1-S7. 

V 


V = volume of low-pressure cylinder; 
v = volume of high-pressure cylinder; 
r = ratio of expansion. 
r Boiler-pressure in ( ^ 

pounds per square inch j 

V 


90 


105 


4.5 




120 

5 


v 


Cylinder-Ratios in Triple-Expansion Engines. 
Whitham: 


Volumes, High to Low. 


Boiler-pressure gauge. 

High pressure. 

Intermediate. 

Low pressure. 

130 

1 

2.25 

5 

140 

1 

2.4 

5.85 

150 

1 

2.55 

6.9 

160 

1 

2.7 

7.25 


For 170 and upward, use quadruple-expansion. 


Common rule: Ratio of volumes of high to intermediate, and that 
of intermediate to low, are each equal to 4 / r, and the ratio of high 
to low = V r 2 . 


Seaton: 

Volumes, High to Low. 


Boiler-pressure, 

absolute. 

High. 

Intermediate. 

Low. 

125 

1 

2 

5 

135 

1 

2 

5.4 

145 

1 

2 

5.8 

155 

1 

2 

6.2 

165 

• 

1 

2 

6.6 


























STEAM-ENGINE PROPORTIONS 


211 


General practice: 

Diameter of intermediate cylinder = 1.5 diameter of high; 
Diameter of low-pressure cylinder = 2.5 diameter of high. 
Length (as given by Whitham): 

Length of bore = L + breadth of piston-ring = to \ inch; 
Length between heads = L + thickness of piston + sum of clear¬ 
ances at both ends. 

Cylinder Thickness. 

t = thickness of cylinder in inches. 

Thurston: t = a pi D + b: 

pi = initial unbalanced steam-pressure in pounds per 
square inch; 

a is a constant, equal to .0004 in short-stroke or 
vertical-cylinder engines, and equal to .0005 in 
long-stroke or horizontal-cylinder engines; 
b is a constant varying from 0 to \ inch. 

Whitham: t = .03 /pD _for any size cylinder; 

t = .003 D 4^p for small cylinders; 
p = boiler-pressure in pounds per square inch. 

Seaton: t = .5 + .0004 p D. 

Unwin: t = .02 D + .5 to .05 D4-.5 (variable). 

Van Buren: t = .0001 D p + .15 V D. 

Weisbach: t = .8+ .00033 p D. 

Haswell: t = .0004 p D +1 for vertical; 

t = .0005 p D+-|- for horizontal. 

Marks: t = .00028 p D. 

Rankine: t = ^ ; 

f = tensile strength of material, with a factor of safety, 
from 30 to 40. 

Barr: t = .05 D + .3 inch, a formula which represents the 

average practice of modern engine-builders. 

Cylinder-Heads. 

Thurston: t = .000333 D p + .25; 

D being diameter of circle in which the thickness is 

taken; 

t = .005 D4/p+.25. 





212 


STEAM-ENGINE PROPORTIONS 


Marks: t = .003 Dj/ p; 

t = .00035 p D. 

Seaton: t = .0005 p D + .25; 

t = .0022 p D + .93. 

Kent: t = .00036 D p + .31, which represents average practice. 


Cylinder-Head Bolts. 

Whitham: Diameter of bolt-circle = D + twice the thickness of the 

cylinder + twice the diameter of bolts. 

Bolts should not be more than 6 inches apart. 

d = DA/ rAr—! 

V 5,000 n 

d = diameter of bolts at root of thread; 
n = number of bolts. 

D 2 p 

n = .0001571 

c 

c = area of one bolt. 

Distance between bolts = four to five times thickness 
of flanges; 

n = .0002 TA. 
d 2 

n = .7 D; 

d = .025 D + .5. 

Both of Barr’s formulas represent average practice 
among builders of modern low-speed engines. 


Marks: 


Thurston: 


Barr: 


Cylinder-Flanges. 

Thurston: Thickness of cylinder-flanges is usually made equal to 
the thickness of flanges of the heads. 

Barr: Thickness of flanges = 1.2 times the thickness of the 

cylinder. 


Clearance. 

Seaton: ^ to § inch for roughness of castings, and iV i inch for 
each working-joint. 


Steam-Pipe. 

Kent: Pipe-diameter = .408 V H, P. 







STEAM-ENGINE PROPORTIONS 213 

Exhaust-Pipe. 

Area = 25 to 50 per cent, greater than area of steam-pipe. 
Valve-Ports. 

Kent: Length of port = .8 D; 

Area of steam-port = ~in feet; 

j vo VJ 

Area of exhaust-port = 1.5 area of steam-port. 

Barr: Area of steam-port = —^ ^ , 

c 

where c = 5,500 in high-speed engines, 
and c = 6,800 in low-speed engines. 


Steam-Chest. 

Thurston: Thickness = .003 D'/p. 

Seaton: Thickness = .7 (.25+ .0005 p D). 

Number and size of bolts are to be determined as for 
cylinder-head. 

V alve-Stem. 

Whitham: DiameterD; 

=-§- diameter of piston-rod. 

Piston. 

Marks: Thickness of piston-head = / L D. 

Barr: Piston-face = .46 D for high-speed engines; 

= .32 D for low-speed engines. 

Whitham: Thickness of piston = breadth of ring + thickness of 
flange on one side to carry the ring + thickness of 
follower-plate. 


Piston-Rings. 

Seaton: w = .63 (.02 D/p + 1). 

Whitham: w = .15 D. 

Unwin: w = .014 d + .08. 

Kent: t = .0333 D + .125; 

w = width of ring in a direction parallel to the axis of 

the cylinder; 

t = thickness of ring on a radial line. 






STEAM-ENGINE PROPORTIONS 


214 

Eccentric Piston-Rings. 

Maximum thickness = .05 I); 
Outside diameter of ring = 1.05 D; 
Inside diameter of ring = .97 D; 
Eccentricity of inner circle = .01 D; 
w = f to | inch. 

Kent: Mean thickness = .0333 D +.125; 
Minimum thickness = § maximum. 


Piston-Rod. 


Unwin: d" = b Dp 7 p; 


p = maximum unbalanced pressure in pounds per square 
inch; 

b =.0167 for iron and .0144 for steel; 


d" = k Dj/p; 

k is a constant, depending on the stress f, allowed in 
the material as follows: 


f 

2,000 

2,500 

3,000 

3,500 

4,000 

k 

.0224 

.02 

.0182 

.0169 

.0158 


f =3,000 to 3,600 in short-stroke direct-acting engines; 
f =2,000 to 2,500 in long-stroke horizontal engines. 

Thurston: d" = v / P ^ + .0125 D; 

v a 

a =10,000 in high-speed engines and 15,000 in low- 
speed engines. 

Marks: d" = .0179 Dp 7 p for iron; 

d" = .0105 D 4 / p for steel. 

Seaton: d" = -^p 7 p; 


F =45 to 60 for direct-acting engines. 

Whit ham: d"=k D; 

k =.l for wrought iron on condensing-engine; 

= .08 for steel on condensing-engine; 

= .125 for wrought iron on non-condensing engine; 
= .10 for steel on non-condensing engine. 






















STEAM-ENGINE PROPORTIONS 


215 


Kent: 
Barr: 


d" = .013 V D 1 

d" = .145/DL 
d" = .ll/D L 


p; 1 = length in inches 

for low-speed engines; 
for high-speed engines. 


L = inches. 


Cross-Head Slides. 


Seaton: 
Rankine: 
Whitham: 
Thurston: 


Barr: 


The thrust on the guide when the connecting-rod 

is at its maximum angle with the line of the 

piston-rod = P, tangent of the angle Z, whose sine 

stroke of piston 

2 X length of connecting-rod 7 

P = .7854 D 2 p; 

* - , P tangent Z 

Area ot slide =---; 

Po 

p 0 = allowable pressure per square inch on slide. 
Po<400 pounds per square inch. 
p 0 = 72.2 pounds per square inch, 
po = 100 pounds per square inch, 
p V < 60,000 and > 40,000; 

V = relative velocity in feet per minute of the rubbing- 
surfaces. 

Area = .63 A for high-speed engines; 

= .46 A for low-speed engines. 


Cross-Head Pin. 


Seaton: 


Barr: 


Projected area = 


.7854 D 2 p . 

1,200 


. ( Length = 1.4 diameter of piston-rod. 

ma engines ^ j}j ame ^ er = i 25 diameter of piston-rod. 

Whitham says the bearing-surface is found by the formula 
for crank-pin design. 

Projected area = .08 A for high-speed engines; 

= .07 A for low-speed engines. 


Connecting-Rod. 

Ratio of length of connecting-rod to stroke: 
Thurston: 2 or 2\ to 1. 

Whitham: 2 to 4J-. 

Marks: 2 to 4; 

d" = diameter of circular connecting-rods larger at the 
middle. 








216 


STEAM-ENGINE PROPORTIONS 


Whitham: cl" (at middle) = .0272 V D 1 4 / p; 

1 = length of connecting-rod in inches; 
cl" (at necks) = 1 to 1.1 diameter of piston-rod; 
Diameter at the crank-pin end = 1.08 times the diam¬ 
eter at the cross-head end. The rod is larger at 
the middle and tapers about ^ inch to the foot. 

Marks: cl" = .0179 D 4 / p, if diameter is greater than length; 

cl" = .02758 V Dll/ p, if the diameter found by the 
previous formula is less than ^ length. 

Thurston: d" (at middle) = a V DLCp + C; 

a = .15 and C = .5 for fast engines; 
a = .08 and C = .75 for moderate speeds. 

Donaldson: cl" (at necks) = .0024 D 2 p. 

Sennett: d" (at middle) =.01818 D 4 / p; 

d" (at necks) = .01666 D 4 / p. 

Seaton: cl" = .02758 V D 1 V p. 

Kent: cl" = .021 D 4 / p. 

Barr: d" = .092 4 / D 1. 

Rectangular Connecting-Rod. 

Thurston: t = .0209 V D 1 4 / p +.47; 

t = distance between parallel sides; 

Depth at cross-head end = 1.5 t; 

Depth at crank-end = 2.25 t. 

Kent: t = .01 D 4 / p + .6. 


Bolts in End of Connecting-Rod. 
Whitham: Diameter at root of thread 
_ D 
= 30 



n p 


D 



4 /n 2 — 1 
n p 


for wrought iron; 


37 V 4 / 


m 


1 


for steel; 


n = 


length of connecting-rod 


length of crank 
p = maximum pressure. 



























STEAM-ENGINE PROPORTIONS 


217 


Cap on End 
Whitham: 


Crank-Pin. 
Marks: 

Whitham 


Thurston 


of Connecting-Rod. 
Depth of cap at centre 
/ n D 2 p 

5.7 1 y 


= 2 


bE/ 


n- 


1 


for rigidity; 



n p 1 


Depth of cap at centre = 1.5 D v , 

y f byn 2 —1 

1 = length of cap between bolt-centres; 

b = breadth of cap; 

E = modulus of elasticity of metal used: 

= 28 million for wrought iron, 

42 million for steel, and 
18 million for cast iron; 

b =\ to 4 length of journal = diameter of neck of con¬ 
necting-rod + \ to \ inch; 

d= depth of cap = .6 diameter of connecting-rod = .8 

, ,, pitch of thread on bolt 
diameter ot bolts +--—-. 


1 = .0000247 f p 1 N D 2 = 1.038 f 


I. H. P. 
L 


1 = .9075 f 


I. H. P. 


L 


1= length of crank-pin journal in inches; 
p 1 =mean pressure in cylinder in pounds per square 
inch; 

f = coefficient of friction, from .03 to .05 for perfect 
lubrication, and from .08 to .1 for imperfect lubri¬ 
cation. 

P N 

for steel pins; 


1 = 
1 = 
1 = 


1 , 200,000 
P N 


600,000 
P V 


for iron pins; 


60,000 d’ 

V = velocity of rubbing-surface in feet per minute; 
P = mean total load on pin; 
d = diameter of pin. 
















218 


STEAM-ENGINE PROPORTIONS 


Rankine: 
Unwin: 


Unwin: 

Thurston: 

Unwin: 

Marks: 

Whitham: 

Barr: 


1 = 
1 = 


P (V + 20) 

44,800 d ‘ 

P 


po cP 

P = greatest load on pin; 

p 0 = pressure in pounds per square inch of bearing; 
po varies from 150 to 200 in small land engines, and 
from 400 to 800 in large land and marine engines; 

, I. H. P. 

1 =a-; 

r 

r = crank-radius in inches; 
a = .3 to .4 for iron pins; 
a = .066 to .1 for steel pins. 


d = 



5.1 
po f 


/P; 


f = twisting-stress, say 5,000 pounds per square inch. 


d = 



5.1 PI 


for wrought iron; increase d 10 per cent. 


9,000 
in case of steel; 

P = maximum load on the piston 


_ 3 


d = .0947 to .0827 y P 1 for wrought iron; 
d = .0827 to .0723 \ P 1 for steel. 

d = .066 V P l 3 D 2 = .945 


H. P. I 3 


LN ’ 

P = maximum steam-pressure in pounds per square 
inch. 


d = .0827 / PI =2.1058 



2 H. P. 1 
LN 


d = .405 V P l 3 . 

Projected area = a = .24 A for high-speed engines; 
a = .09 A for low-speed engines; 

1 = .3 — +2.5 for high-speed engines; 

H. P. 

1 = .6 —j-^+2 for low-speed engines. 





















STEAM -ENGINE PR O PO RTIONS 


219 


Crank. 

rpi , ■[ .7854 f D 2 p R secant z 1 

inurston: b =---; 

a d 2 

b = thickness of web 
d = width of web; 

1 = radius of crank; 

p = maximum unbalanced pressure in pounds per 
square inch; 

z = angle of rod with centre-line of the engine; 
f = factor of safety. 

The diameters of the hubs are about twice the diameters of the 
corresponding shafts, and d, at either end, is three-fourths the diameter 
of the adjacent hub. 

Empirical rules adopted by builders give for wrought iron: 

Hub-diameter = 1.75 to 1.8, the least diameter of that 
part of the shaft carrying full load; 

Eye-diameter = 2 to 2.25 times the diameter of the 
inserted portion of the pin; 

Hub-depth = 1.0 to 1.2 diameter of shaft; 

Eye-depth = 1.25 to 1.5 diameter of pin; 

Web-width = .7 to .75 width of adjacent hub or eye; 
Web-depth = .5 to .6 depth of adjacent hub or eye. 

rm w f k (2 y) 2 

Whitham: W x =-—^—; 

o 

k = thickness parallel to shaft, and generally = .75 shaft- 
diameter ; 

2 y = variable width; 

x = distance from crank-pin centre to place where 2 y 
is measured; 

f = allowable stress per square inch of material; 

\/ n 2 +1 

W = .7854 D 2 p--—, 

n 

. length of connecting-rod 

where n = —--r—*-i-• 

length ot crank 

For a two-cylinder engine W = 1.414, and for a three-cylinder 
engine W = 2 times the above value. 







220 


STEAM-ENGINE PROPORTIONS 


Shaft. 


When designed for combined twisting and bending: 

s / 5 1 T' 

Whitham: d = y j—-; 


T = greatest twisting-moment on shaft due to load on 
the piston; 

M = greatest bending-moment on shaft due to load 

on the piston; _ 

T' = Equivalent twisting-moment = M + V M 2 + T 2 on 
outer journal for overhung crank; 


T = 


M 

2 



+ T 2 for double, crank arm. 


The above formula gives safe values except with very heavy fly¬ 
wheels, where the shaft must be designed with reference to bending 
due to the weight of fly-wheel and shaft. 

Kent: d = .43 D for long-stroke engines; 
d = .4 D for short-stroke engines. 

For two cranks at 90 degrees: 

d = 1.932 j/T ; 


T=maximum twisting-moment produced by one piston; 
f = safe-working shearing-strength of material. 


Length of Shaft-Bearings. 

Marks: 1 = .0000247 f p N D 2 ; 

f = coefficient of friction; 

p = mean pressure in pounds per square inch on piston. 


Unwin: 


Barr: 


, .4 H. P. 

; 

r = radius of crank in inches; 

1 = (.002 N + 1) d for wrought iron; 
1 = (.0025 N +1.25) d for steel. 

1 =2.2 d for high-speed engines; 

1 =1.9 d for low-speed engines. 


Fly-Wheels. 


Thurston: 


Di = diameter in feet = 


3,820 
N ' 


Di =4L; 

W = weight = 1,000,000 --— 

N 2 Di 2 


for automatic valve- 












STEAM-ENGINE PROPORTIONS 


221 


gear engines and ordinary forms of non-condensing 
engines with a ratio of expansion from 3 to 5; 
p = mean steam-pressure in pounds per square inch; 
w — a A L . 

N 2 Di 2? 

a ranges from 40 to 60 million, with an average value of 
48 million. 

Rankine: W = 1,900,000 ^ ; 

\ Dr R 

V = variation of speed per cent, of mean speed. 

I) 2 H 

Stan wood: W = 2,800,000 — ; 

Di“ N- 

D= diameter of cylinder; 

S = stroke in inches. 

Fly-Wheel Rims. 

. t Dj 


t = 


N 2 


Fly-Wheel Arms. 

WL 


Torrey: b = 
W 


30 cl 2 ’ 
S y 
n ; 


Unwin: d =. 


W = load in pounds acting on one arm; 

L = length of arm in feet; 

S = strain on belt in pounds per inch of width, taken at 
56 for single and 112 for double belts; 
y = width of belt in inches; 
d = depth of arm at hub in inches = major axis; 
b = breadth of arm at hub in inches = minor axis. 

In using the formula assume depth. 

Depth and breadth can be reduced by about J at rim. 

3 


>337 



B Di 


n 


for single belts; 


d = .798 



B Di 


n 


for double belts; 


b = .4d; 

B = breadth of rim. 












222 


STEAM-ENGINE PROPORTIONS 


Maximum Speed of Fly-Wheels. 

1 527 

80 feet per second = 4,800 feet per minute; R. P. M. = • . 

88 feet per second = 5,280 feet per minute; R. P. M. =—jy-. 

100 feet per second = 6,000 feet per minute; R. P. M. = 1 . 

Maximum Diameter in Feet of Fly-Wheels. 

80 feet per second = 4,800 feet per minute; 

88 feet per second = 5,280 feet per minute; 

100 feet per second = 6,000 feet per minute; 

D = diameter of wheel in feet. 


T) _ R527 
R. P. M.‘ 
1,680 

“R. p.m: 
n _ R910 

“r. p.m; 


The following tables of the principal dimensions of high- and low- 
pressure cylinders have been compiled by Mr. L. L. Willard, a designer 
of Corliss engines, and although they may not conform to the practice 
of every builder, may be a good schedule of reference for the various 
sizes of cylinders for the high and low pressures of 150 and 50 pounds 
respectively. 


Table XXX. —High-Pressure Cylinder-Dimensions for 150 Pounds Steam- 

Pressure. 



CD 

£-h 

O 

U-> 

O m 

° a5 

U-i 

O 

M 

1 

u-< . 

C G 

* 4-1 

o 

4- . 

C 0) 

4m 0) 

C Q. 

Jjj 

4-* 

* 4-1 

c 

4— | 

O C 

Size. 

; c 

' 1 
c 

o 

O 

Thickness 

barrel. 

Thickness 

steam-che 

wall. 

Thickness 

exhaust-ch 

wall. 

Diameter 

valves. 

u 

cj 

V 

£> 

i 

> 

cj 

> 

Depth of cy 
der-head 

ITi O 
tn +-> 

O ”C 

H gg 

Thickness 

bull-ring 

piston. 

Diameter 

steam-pip 

STS. 

« « 

S 3 

03 2 

Q * 

CJ 

*5 

i 

bC 

.S 

*c 

Q 

Number ( 
studs. 

Diameter 

studs. 

Diameter 

foundatioi 

bolts. 

A 

B 

C 

D 

E 

F 

G 

H 

i 

J 

Iv 

L 

M 

N 

0 

P 

12 

121 

1 

1 

7 

8 

31 

21 

5f 

4 

51 

5 

6 

15 

10 

7 

8 

If 

14 

14* 

1 

1 

7 

S 

4 

21 

5* 

4 

51 

5 

6 

17 

10 

1 

If 

16 

161 

If 

11 

1 

41 

91 

- J 2 

5f 

4 

51 

6 

7 

19 

12 

l 

If 

18 

181 

11 

11 

1 

5 

3 

6 

5 

61 

7 

8 

21 

14 

if 

H 

20 

201 

U 

H 

1 

5 

3 

6 . 

5 

61 

8 

9 

23 

16 

if 

If 

22 

221 

11 

if 

1* 

6 

34 

74 

51 

71 

9 

10 

25f 

18 

if 

If 

24 

241 

If 

if 

1* 

6 

34 

81 

51 

81 

10 

12 

27* 

18 

H 

If 

26 

261 

If 

11 

11 

61 

31 

81 

rci 

84 

10 

12 

29 

20 

if 

If 

28 

281 

u 

U 

11 

r* 

( 

3f 

10 

7 

10 

11 

13 

31* 

20 

if 

If 

30 

301 

if 

11 

11 

71 

4 

10 

7 

10 

12 

14 

34 

24 

if 

2 

32 

321 

If 

11 

11 

8 

4 

10 

7 

11 

12 

14 

36 

24 

if 

2 

34 

341 

If 

If 

11 

84 

4 

114 

8 

12 

14 

16 

38 

28 

if 

2 

36 

36 * 

If 

If 

11 

9 

41 

121 

8 

12 

14 

16 

40 

32 

if 

2 


































































STEAM-ENGINE PROPORTIONS 


22,3 


Table NXXI. —Low-Pressure Cylinder-Dimensions for 50 Pounds Steam- 

Pressure. 


Size. 

1 

Counterbore, j 

Thickness of 
barrel. 

Thickness of 
steam-chest 
wall. 

Thickness of 
exhaust-chest 
wall. 

Diameter of 
valves. 

Valve-bearing. 

Depth of cylin¬ 

der-head. 

Thickness of 

solid piston. 

Thickness of 

bull-ring 

piston. 

Diameter of 

steam-pipe. 

Diameter of 

exhaust-pipe. 

Drilling-circle. 

Number of 

studs. 

Diameter of 

studs. 

Diameter of 

foundation- 

bolts. 

A 

B 

C 

D 

E 

F 

G 

H 

I 

J 

K 

L 

M 

N 

O 

P 

20 

201 

if 

1 

7 

8 

5 

3 

6 

6 

64 

7 

8 

23 

16 

7 

8 

14 

22 

22} 

if 

1 

7 

8 

6 

34 

74 

6 

64 

8 

9 

25f 

18 

7 

8 

if 

24 

24} 

if 

1 

7 

8 - 

6 

34 

8* 

6 

8 

9 

10 

27} 

18 

1 

if 

26 

26} 

1 3 
1 8 

If 

1 

64 

34 

84 

6 

8 

9 

10 

29 

20 

1 

if 

28 

28} 

if 

if 

1 

7 

3f 

10 

7 

9 

10 

12 

31J 

20 

1 

if 

30 

301 

14 

if 

1 

74 

4 

10 

7 

10 

10 

12 

34 

22 

1 

2 

32 

32i 

1} 

if 

1 

8 

4 

10 

8 

12 

12 

14 

36 

22 

If 

2 

34 

34i 

14 

if 

If 

84 

4 

10 

8 

12 

12 

14 

38 

24 

1 8 

2 

36 

361 

1 8 

if 

if 

9 

44 

12 

84 

14 

14 

16 

40 

26 

H 

2 

38 

381 

If 

if 

if 

9 

44 

12 

84 

14 

14 

16 

42 

28 

if 

2 

40 

401 

If 


if 

9 

44 

12 

84 

15 

16 

18 

44 

28 

if 

2 

42 

42i 

If 

14 

if 

10 

5 

13 

9 

15 

16 

18 

46 

28 

if 

2 

44 

44i 

If 

14 

if 

10 

5 

13 

9 

15 

16 

18 

48 

32 

if 

2f 

46 

46f 

If 

14 

if 

10 

5 

14 

94 

164 

18 

20 

50 

32 

if 

2f 

48 

481 

If 

14 

if 

11 

6 

14 

104 

164 

18 

20 

52 

32 

if 

24 

50 

50 J 

n 

if 

14 

11 

6 

15 

10i 

174 

20 

22 

54 

36 

if 

24 

52 

52i 

n 

if 

14 

12 

7 

15 

104 

174 

20 

22 

56 

36 

if 

24 

54 

54} 

if 

if 

14 

12 

7 

15 

11 

18 

20 

22 

58 

36 

if 

2f 

56 

56} 

2 

if 

14 

12 

7 

16 

12 

18 

20 

22 

60 

36 

if 

2 f 

58 

58} 

2 

1 * 

14 

12 

7 

16 

12 

20 

22 

24 

62 

40 

if 

2 f 

60 

60} 

2 

1 £ 

14 

12 

7 

16 

12 

20 

22 

24 

64 

40 

if 

2f 


The piston of a steam-engine has been a matter of much study 
with engine-designers in order to counteract the wear of both piston 
and cylinder from excessive frictional action. The early form of a 
solid bearing-surface drifted 
into the form of a solid pis¬ 
ton with one or more plain 
and eccentric snap - rings 
with followers, which later 
developed into a composite 
piston of almost as many 

variations as there are build- p IG> 169.—Composite piston, 

ers of engines, for almost 

every designer has a kink of his own, which he always legalds as the 
best. In Fig. 169 is shown a composite piston, consisting of a spider 
and a follower-plate that clamps a bull-ring, which is made adjustable 














































































































224 


STEAM-ENGINE PROPORTIONS 



Bull Ring 


Fig. 170.—Segmental piston. 


by lock-screws for keeping the piston-rod concentric with the cylinder; 
the lock-screws are threaded in the web of the spider, with lock-nuts 
on the inside. On the left side of the cut is shown the single-snap 
spring-ring held out by flat springs against shoulders, and at the right 

a double spring with the same con¬ 
struction. This piston is used on the 
engines of the Murray Iron Works 
Company. 

Another model, Fig. 170, has a 
packing-ring made in six segments, 
with halved joints, and set out against 
the cylinder-walls by small coil-springs 
held in brass sockets screwed into the bull-ring. The bull-ring is 
adjusted by lock-screws in the web of the spider. 

In Fig. 171 are represented the cross-head and a half-section of the 
piston as made by the Hewes & Phillips Co. 

The cross-head is secured to the piston-rod by a thread and nut, 
or a taper fit with a cross-key which draws the rod firmly to the shoul¬ 
der. The wedge form of a gib at the top and bottom of the cross-head 
provides means for adjustment. 

The sliding surfaces of the gibs are faced with antifriction metal, 
and the surfaces of these gibs are amply large for the severest duty. 

The design of the 
cross-head is such as 
to entirely avoid the 
springing of the piston- 
rod or any tendency 
to force the cross-head 
out of line. 

The piston is a 
strongly ribbed cast¬ 
ing, securely fastened 
to the piston-rod by 
forcing. It is further 
secured by a strong and 



Fig. 171.—Hewes & Phillips cross-head and piston. 


substantial key midway in its bearing in the piston. The end of the 
rod is also riveted. ' There is a tendency in all pistons to wear down 
or get out of centre. When this occurs the piston-rod is liable to be 































































































STEAM-ENGINE PROPORTIONS 


225 


grooved and the gibs of the cross-head to wear unequally on their 
opposite ends. To obviate this the piston is furnished with a solid 
bull-ring, against which suitable screws with jam-nuts are provided 
loi adjustment. Ry this means perfect alignment of the piston with 
the cylinder can be readily secured. 

The bull-ring is a solid casting turned in such a manner as to have 


a full semicircular bearing on the lower half of the cylinder. At 
either end of the bull-ring are narrow piston-rings, which wipe over 



Fig. 172.—Harris piston. 



the counterbore at each end of the cylinder, so that no shoulders 
can be worn on its surface. 

In this design of piston the packing is self-acting in its adjustment, 
while the adjustment for alignment can be readily made by removing 
the follower and setting up the screws provided for this purpose. 

In Fig. 172 are shown a plan and section of the Harris piston, con¬ 
sisting of a seven-part spider and as many locked set-screws for central 
adjustment. The rings are also in seven spliced segments, set out 
with helical springs. 

As the piston, together with the piston-packing, is one of the 
most important parts of the engine, particular attention has been 
given to its design and construction. 

It is forced upon the rod by hydraulic pressure, which in the 













































226 


STEAM-ENGINE PROPORTIONS 



Fig. 173.—Nordberg cross-head. 


larger sizes the bearing is made the full thickness ot the piston, with a 
steel collar screwed on the end of the rod; otherwise a recessed nut, 
as shown. 

The bull-ring extends over the full width of the piston, overlapping 
the piston and the follower. It is grooved to receive the segmental 
packing. 

All of the Harris pistons are fitted with bronze adjusting-screws, 
so that they can be kept centrally within the cylinder and that the rod 

may always be in perfect alignment. 

In Fig. 173 is shown a cross-head 
of the Nordberg engine, which is ad¬ 
justed by a top and bottom wedge 
and screws with lock-nuts. The ad¬ 
justment of the cross-head for keeping 
the piston-rod in the central line and 
parallel with the piston-bore is an 
essential part of engine-management; 
and these designs are most numerous, 
but all having or seeking the required 
ideal of perfect control and fixedness of the adjustment. 

In Fig. 174 is shown a similar arrangement in the cross-head of 
the Murray engine, with cylindrical Babbitted bearings on wedge- 
shoes that are bolted to the 
mam block. 

The design of the connect¬ 
ing-rods and the method of 
adjustment of their boxes 
vary very much with engine- 
builders, the wedge and screw 
being in general use. 

In Fig. 175 is shown the 
rod-end used by the W. A. 

Harris Company, in which the 

inner box has an inclined back with a wedge and draw-screws on each 
side. The screw sprevent a possible movement of the wedge by the 
motion of the rod. 

In Fig. 176 is shown the connecting-rod end of the Filer & Stowell 
Co., on which the adjusting-wedge is placed horizontally at both ends 




Fig. 174. —Cylindrical cross-head. 






































































































STEAM-ENGINE PROPORTIONS 227 

of the rod, and adjusted by a collar-bolt and lock-nuts. A set-screw 
underneath is added as a safety-check. 

The^main bearings of a.steam-engine require the same care as its 
other running parts—not only in providing for its proper lubrication, 
but also as the means for taking 
up of the boxes to meet the wear. 


Fig. 175. —Cross-key box. Fig. 176. —Side-key box. 

In horizontal engines the thrust of the piston may cause a pound in 
the main bearing by looseness from wear, and in vertical engines the 
wear in the journal-boxes is vertical from the action of the piston, 
but may also be crosswise from the belt-pull. 



In Fig. 177 are shown a half-view and half-section of the self- 
lubricating main bearing of the Bayley engine, in which a ring dips 
into the oil-chamber below, and, rolling over the top of the journal, 
gives it a constant and economical oil-feed. A gauge-glass connected 

























































































228 


STEAM-ENGINE PROPORTIONS 


to the bottom of the chamber shows the height of the oil, and the 
drip-cock allows of drawing off the oil and cleaning the chamber 
when required. 

The adjustable main bearing used on the Todd engine is shown in 
section in Fig. 178, in which the quarter-boxes on each side are ad¬ 



justed by wedges at their back and by long stud-bolts reaching through 
the cap with locking-nuts. The cap of this bearing has a hand-hole 
and cover large enough to allow the journal-surface to be examined 
while the engine is running. 

THE FLY-WHEEL 

The most important element in controlling the motion of a steam- 
engine is that which equalizes its transmission of speed. The fly¬ 
wheel takes action before the governor in all motors or engines that 
receive their impulse in unequal increments, and the more unequal 
the impulse the more important is the office of the fly-wheel. 

Its power to equalize the speed of revolution depends upon its 
weight and rim-velocity, while the governor only regulates the im¬ 
pellent force that drives the engine. Solid fly-wheels of cast iron as 
ordinarily made are limited to a rim-speed of about one mile per minute, 
with their usual diameter limited at 8 feet, and from 8 to 16 feet in 
halves, divided through the arms or between them. Above 16 feet 
in diameter sectional wheels are of the usual construction, with the 
joints at the end of the arms, and sometimes with the arm and 
section cast in one piece. 


















































STEAM-ENGINE P ROPORTIONS 229 

1/9 shows a channel rim-wheel, as usual made in halves, and 
Pig. ISO a heavy rim-wheel in sections bolted to the arms. 

. The ultimate strength-efficiency of the wheel divided in halves, 
with ordinary bolting at hub and rim, is about 25 per cent., the sec- 



Fig. 179.—Wheel in halves. 



Fig. 180.—Sectional wheel. 


tional about 50 per cent., and with heavy rim-wheels reenforced with 
links shrunk on, an efficiency of 60 per cent, may be obtained. 

In the following table are given the number of revolutions of solid 
wheels and the different models of sectional wheels according to their 
percentage of efficiency, with a speed-margin of safety of one-third 
of their tensile strength. 

This table has been computed on the assumption of 100 feet per 
second rim-speed as the maximum safe velocity of the rims of solid 
cast-iron wheels. 

For sectional wheels with flange-joints between the arms, 
100X4/.25 = 50 feet per second. 

For sectional and belt wheels having joints at the end of the arms 
and rim-sections, 100 X V ■ 50 = 70.7 feet per second. 

For thick-rimmed sectional w heel s having rim-joints reenforced 
by steel links shrunk on, 100 X V ■ 60 = 77.5 feet per second. 

From this may be deduced the number of revolutions for any 
diameter of the four conditions of efficiency: For solid wheels, 1,910 
diameter in feet; for sectional belt-wheels and split wheels with 
joints between the arms, 955 4 - diameter in feet: for sectional belt- 
wheels with additional joints at end of arms, 1,350 -f diameter in 
feet; for thick-rimmed sectional wheels having rim-joints reenforced 
by steel links shrunk on, 1,480 -f- diameter in feet. 

The weight and diameter of a fly-wheel are matters of much con¬ 
sideration in their design to meet the most economical conditions of 
the variable forces due to impulse, local limitations, and weight of 
metal to satisfy the requirement. 


















230 


STEAM-ENGINE PROPORTIONS 


Table XXXII. —Safe Speed for Cast-Iron Fly-Wheels. 


Efficiency of Rim-Joint. 


1.00 


,25 



.60 



Diameter in feet. 

i 

R. P. M. 

R. P. M. 

R. P. M. 

R. P. M. 

1 

1.910 

955 

1,350 

1,480 

2 

955 

478 

675 

740 

3 

637 

318 

450 

493 

4 

478 

239 

338 

370 

5 

382 

191 

270 

296 

6 

318 

159 

225 

247 

7 

273 

136 

193 

212 

8 

239 

119 

169 

185 

9 

212 

106 

150 

164 

10 

191 

96 

135 

148 

11 

174 

87 

123 

135 

12 

159 

80 

113 

124 

13 

147 

73 

104 

114 

14 

136 

68 

96 

106 

15 

128 

64 

90 

99 

16 

120 

60 

84 

92 

17 

112 

56 

79 

87 

18 

106 

53 

75 

82 

19 . 

100 

50 

71 

78 

20 

95 

48 

68 

74 

21 

91 

46 

65 

70 

22 

87 

44 

62 

67 

23 

84 

42 

59 

64 

24 

80 

40 

56 

62 

25 

76 

38 

54 

59 

26 

74 

37 

52 

57 

27 

71 

35 

50 

55 

28 

68 

34 

48 

53 

29 

66 

33 

47 

51 

30 

64 

32 

45 

49 


For automatic valve-geared engines we quote Professor Thurston’s 
general rule as the means of practice to meet the special conditions 
of engine-running: 

Weight of fly-wheel = 250 , 000 ^^ i n which A = area of piston 

in square inches; S = stroke in feet; p = mean effective pressure; 
R = revolutions per minute; D = outside diameter of fly-wheel in feet. 






























STEAM-ENGINE PROPORTIONS 


231 


As rim-velocity increases as the diameter, and as centrifugal force 
increases as the square of the rim-velocity, the centrifugal force must 
bear a safe proportion to the minimum tensile strength of ' the rim 
for assigning the weight and diameter of a fly-wheel for any assumed 
speed. 

The total strain in a fly-wheel rim by centrifugal force is: ---^ 2 , 

g R 

in which W = the total weight of the rim in pounds; V 2 = the square 
of the velocity of the rim; g = the gravity 32.16, and R = the radius of 
the wheel in feet. 

For example: a wheel-rim 1 inch square and 12 inches outside 
diameter would have a mean diameter of 11 inches X 3.14 = 34.54 
cubic inches; at .25 pounds per cubic inch = 8.64 pounds. At a 
speed of 1,910 revolutions per minute, 1,910x3.1416 = 6,000 feet per 

minute, or 100 feet per second. Then X = 5,360 pounds, 

the total strain due to centrifugal force; and as there are two sides 

to the rim on which this force is divided, then = 2,680 pounds 

hmi 

strain per square inch, or about one-half the elastic limit and one- 
fourth of the lowest tensile strength of cast iron. 

THE CONNECTING-ROD ANGLE 

The position of the piston in parts of its stroke does not coincide 
with its position in parts of the crank-rotation, as will be seen by 
comparing the scales A and B, Fig. 181, made from the angular posi¬ 
tions of a connecting-rod of twice the stroke in length. The upper 
scale, A, is in equal parts of the piston-stroke, while the lower scale, B, 



Fig. 181.—Piston- and crank-stroke. 













232 


STEAM-ENGINE PROPORTIONS 


represents the corresponding scale for equal increments of the crank- 
pin half-circle for one stroke. It may be noted by the scale that at 
the half-stroke of the crank the piston has advanced about f of T V of 
its stroke, and that in the return-stroke the advance will be the same, 
making 1^- of y-g- of its stroke difference in the positions of the piston 
during a revolution. The displacement of the position of the piston 
at half-crank stroke may be readily computed—say, for a 10-inch 
stroke and 20-inch piston-rod—by the right-angle equation, as follows: 
20 2 —5 2 = 375, and ^375 = 19.365, and 20-19.365 = .625, or f inch, 
or a difference of 1\ inches in the forward and back stroke of the 
piston. Short eccentric-rods produce the same irregular motion of 
the valve in a small degree by advancing its position at the middle 
of each stroke. 

There is much in steam-engine design that cannot be detailed in 
a general treatise as shown in this work. 

Experience is the most important factor in the details of construc¬ 
tion that a designer should have in order to accomplish good results 
from the theory and in the line of modern practice. 

The foregoing chapter is characteristic of the views of authors on 
the proportions of the leading parts in construction design; they 
may vary somewhat from the most recent practice of builders, but 
will make a good study for the inquiring engineer and the student 
in steam-engine design. 



CHAPTER XV 


THE SLIDE-VALVE AND VALVE-GEAR 


The slide-valve of our forefathers was the so-called D valve, with¬ 
out lap or lead, which has long since been relegated as a memorial 
of primitive experience. The D valve and its congener, the piston- 
valve, as we now understand them, are modelled after our modern 
ideas of the economy derived from expansion, compression, and 
steam-leach For this purpose they are designed with extensions of 
their faces for steam- and exhaust-lap, and operated by the angular 
position and throw of the eccentric for steam- and exhaust-lead; all 
cf which are made variable to meet the special contingencies of 
design in engine-economics. 

In Fig. 182 we illustrate the modern type of the D valve with 
steam- and exhaust-lap, and in its central position. 

The portion a is the “steam-lap” or “outside lap,” and the por¬ 
tion b the “exhaust-lap” or “inside lap,” and in order to open either 
port to steam or exhaust, it is necessary 
for the valve to travel from mid-position a 
distance equal to these laps, and for a full 
port-opening a greater distance than the 
amount of all the laps, or equal to the 

steam-lap and port width. ;p IG ^g 2 _ d Ya } ye> 

In the ordinary type of plain slide-valve 



engine with throttle-valve the cut-off is fixed, and there is no adjust¬ 
ment for speed variation except through a governor and throttle- 
valve; while the automatic high-speed engines are provided with fly¬ 
wheel governors which vary the throw of the eccentric and the cut-off. 

Since the valve-travel depends upon the lap and lead, both of 
which are frequently adjustable irrespective of the eccentric, the 
conditions in the cylinder also depend upon these quantities, and 
when the latter are determined the eccentric must operate the valves 

so as to produce the required lead. 

The operation of the valve is determined by inspecting or meas- 

233 
















234 


THE SLIDE-VALVE AND VALVE-GEAR 


uring its movements, the eccentric thus far having no direct influence 
upon the result. AVhen the lap and lead are decided upon, the 
eccentric is turned until the desired lead is obtained, which is meas¬ 
ured at the valve and not at the eccentric. As the lead with a given 
lap depends more or less upon the lap and upon lost motion in the 
gear, it is evident that these quantities must first be determined 
and the eccentric moved backward or forward on the shaft until 
the desired movement of the valve is obtained. 

When the required steam-distribution has thus been established 
the eccentric will occupy the proper position for producing the re¬ 
sults, and it will be seen that it makes absolutely no difference to the 
engineer whether the eccentric leads the crank by 98 or 105 or any 
other number of degrees. The position of the eccentric in cases of 
valve-setting and gear-adjustment takes care of itself by its move¬ 
ment to meet the valve-adjustment. 

It will no doubt be apparent that the truly important point to 
be observed is the effect of lap and lead on the steam-distribution. 
When these have been properly determined and the movements of 
the valve regulated and timed to produce them, the eccentric will 
be found to be located at precisely the proper angle with reference to 
the crank. 


SIMPLE SLIDE-VALVE GEAR 

The relative position and motion of the eccentric-rod and valve- 
rod are points of consideration in the design of a plain slide-valve 
engine. 

In determining the position of the eccentric in cases where a 
rocker-arm intervenes between the eccentric- and valve-rods, con¬ 



sideration must be given the point at which the rocker-arm is pivoted. 
If the rocker-arm is pivoted so that the valve- and eccentric-rods 














THE SLIDE-VALVE AND VALVE-GEAR 


235 


both move in the same direction at the same time, the eccentric is 
set in the positions shown in Figs. 183 and 184, which illustrate re¬ 
spectively the different parts of the gear in the proper relative positions 
when it is desired to have the engine run “over” and “under.” 



When the rocker-arm is pivoted so that the valve- and eccentric- 
rods move in opposite directions, then the eccentric must be set in 
the positions shown in Figs. 185 and 186, which are directly oppo¬ 
site to the positions shown in Figs. 183 and 184. Here, too, the 
illustrations show the engine set to run “over” and “under.” 



Fig. 185.—Indirect gear for running “over.” 


The eccentric-rod may be said to be indirect-acting, for with the 
rocker-arm pivoted as shown in the diagram the eccentric-rod has 
a movement that is directly opposite to that of the valve-rod. 

This will be made plain by a study of the diagrams shown. 



Fig. 184 shows the correct position of the eccentric when the 
engine is to run “under” and when the particular valve-gear shown in 
Fig. 183 is used. 






































236 


THE SLIDE-VALVE AND VALVE-GEAR 


In the diagrams, 0 represents the crank-shaft, A the crank-pin, 
C and I) the points at which the valve- and eccentric-rods are con¬ 
nected to the rocker-arm, E the pivot for the rocker-arm, and F and 
G the necessary joints for the valve-stems and piston-rods. 

A good rule to bear in mind when setting engine-valves that 
are operated by these simple types of valve-gear is: When a slide- 
valve is used and the eccentric- and valve-rods move in the same 
direction, set the eccentric ahead of the crank and make the angle 
between them 90 degrees plus the angle of advance. 

The above rule holds good whether the engine runs “under” or 
“over.” On the other hand, when the valve- and eccentric-rods 
move in opposite directions, the eccentric must be set behind the 
crank, and the angle between them will be 90 degrees minus the 
angle of advance. 

The proper positions of the valve must be determined at the 
valve, whether the position of the eccentric be located first or last; 
but when observing the valve first, no attention need be paid to the 
position of the eccentric. 

Few would care to undertake the work of placing the centre of 
the eccentric at a given angle to the centre of the crank, and no 
matter how carefully the work may be done, an inspection of the 
valve, in nine cases out of ten, will prove the time and labor to have 
been expended uselessly. 

The length of the port-opening is usually equal to or little less 
than the cylinder diameter. The width of the bridge should be 
amply sufficient to prevent steam leaking past the seal into the ex- 




haust-port or to prevent the over-travel 
uncovering the steam- and exhaust-ports 
at the same time. 

In order that the exhaust-port shall at 
no time be contracted to a less area than 
that of the steam-port, its width should 
be such that it will at all times retain an 
opening under the valve equal to the area 
of the steam-port at least. 

In Fig. 187 is shown a good-propor¬ 
tioned D slide-valve at middle and extreme travels with the ex¬ 
haust-port of a width more than double the width of the steam- 



Fig. 187.—Middle and extreme 
valve-positions. 
































THE SLIDE-VALVE AND VALVE-GEAR 237 

port, which allows of excess of valve-travel without restricting the^ 
exhaust-opening. 

Such a valve, having an outside lap of \ inch, inside lap of inch, 
over-travel of -f inch, with ports and bridges 1 inch each, will have a 
travel of-|- + -|- + f + lX 2 = 4 inches. 

In laying out a valve it often happens that in order to have the 
points of release and compression occur at a particular period the 
inside or exhaust lap becomes zero, or else leaves the exhaust-port 
slightly open at mid-position. This port-opening is known as nega¬ 
tive lap, and it is a common occurrence to find a valve possessing 
negative lap when not so designed, due to the effect of the rod-angu¬ 
larity which was neglected in the valve-diagram. This only occurs, 
however, when the original exhaust-lap is very small, so that the 
small error caused by the angularity of the 
rod neutralizes the shortage in exhaust-lap 
entirely. 

The zero and negative laps are shown in 
Fig. 188, in which a is the point of opening 
of the exhaust, and b the point of cut-off Fig. 188.—Negative inside lap. 
for the exhaust. 

The lead to be given to a valve depends largely upon the style 
of engine, and must be governed entirely by experience. It may 
vary from 0 up to and even above -§ inch. Slow-running engines 
require less lead than those running at a high speed, and engines 
having a high compression require less than those without, since 
the clearance-space is filled with compressed steam whose pressure is 
nearly equal to that of the entering live steam. In locomotives it 
varies from 0 to \ inch, and in marine practice from 0 to 1^- inches. 
In stationary practice the values may vary from 0 to \ inch, but 
seldom more, unless in very high-speed work. The angle of lead, 
which is the angle that the crank makes with the dead points at 
admission, varies between 0 and 8 degrees in stationary practice, 
and seldom over 10 degrees in marine practice. 

The inside lead, or what would be called the exhaust-lead, is 
often greater. It is provided for the purpose of opening the exhaust- 
port early. Weisbach gives the proportion of ¥ V to tV of the valve ~ 
t ravel. 

The outside lap may vary from J inch to lj- inches in locomotives, 








238 


THE SLIDE-VALVE AND VALVE-GEAll 


while in marine engines it may run from } inch to 3^ inches. The 
inside lap may vary from a negative value to \ inch, and in marine 
practice will often run as high as 1^- inches. 

The eccentricity will vary largely with the style of engine and 
valve-travel desired, but it should be no greater than necessary, 
owing to the wear on the reciprocating parts. In marine engines 
it may vary from 5 to 8 inches, or even more in large units. 

Changing the dimensions of any part of the valve which determines 
either the lap or lead, or changing the angular advance, alters the 
steam-distribution. The accompanying table shows at a glance just 
what particular effect each change has upon this distribution: 


Table XXXIII.—Effect of Changing Outside Lap, Travel, and 

Angular Advance. Thurston. 


Change. 

Admission. 

Expansion. 

Exhaust. 

Compression. 

Increase of 
outside lap. 

Begins later. 

Ceases sooner. 

Occurs earlier. 
Continues longer. 

Unchanged. 

• 

Unchanged. 

Decrease of 
outside lap. 

Begins earlier. 
Ceases later. 

Begins later. 

Period shortened. 

Unchanged. 

Unchanged. 

Increase of 
inside lap. 

Unchanged. 

Begins as before. 
Continues longer. 

Begins later. 

Ceases earlier. 

Begins sooner. 
Continues longer. 

Decrease of 
inside lap. 

Unchanged. 

Begins as before. 
Period shortened. 

Begins later. 

Ceases earlier. 

Begins later. 

Period shortened. 

Increase of 
travel. 

Begins sooner. 
Ceases later. 

Begins later. 

Ceases sooner. 

Begins later. 

Ceases later. 

Begins later. 

Ends sooner. 

Decrease of 
travel. 

Begins later. 

Ceases earlier. 

Begins earlier. 
Ceases later. 

Begins earlier. 
Ceases earlier. 

Begins earlier. 
Ceases later. 

Increase of 
angular advance. 

Begins earlier. 
Period unchanged. 

Begins sooner. 
Period unchanged. 

Begins earlier. 
Period unchanged. 

Begins earlier. 
Period unchanged. 

Decrease of 
angular advance. 

Begins later. 

Period unchanged. 

Begins later. 

Period unchanged. 

Begins later. 

Period unchanged. 

Begins later. 

Period unchanged. 


EXCESSIVE COMPRESSION 

The compression is sometimes represented in indicator-diagrams 
as excessive; with plain D valves its relief cannot always be found in 
the valve-gear adjustment. A method of changing the exhaust-lap 

























































THE SLIDE-VALVE AND VALVE-GEAR 


239 


has been proposed, and is shown in Fig. 189. It consists in filing off 
the edge of the lap for small amounts, and for a further change filing 
half-round grooves across the edge of the lap and the port at opposite 
points. This method of reducing compression will slightly interfere 
with the expansion-line, but not to any serious extent. 



Fig. 189. —Changing the exhaust-lap. Fig. 190. —Balanced valve. 

The modifications of the D valve for more perfect action have 
developed some curious yet valuable features in their design. 

The balanced valve is now largely in use, and one of its forms is 
shown in Fig. 190, which carries in the back a ring which bears against 
a smooth seat on the valve-chest cover and is supported by springs. 
The cavity at the back of the valve may be open to a condenser or 
through the back of the valve to the exhaust. 

As one representative of. the double-admission type, the Allen 
balanced valve, illustrated in Fig. 191, has a broad, double-ported 
steam-passage through the body and a relief-port from the cavity at 
its back to the exhaust-cavity. The ports of the supplementary 
passage are so located as to take steam to the port at the moment of 




Fig. 191.— Allen balanced valve. Fig. 192.— Double-ported slide-valve. 

opening of the lap-edge of the valve, from the simultaneous opening 
of the supplementary port at the other end. This passage never com¬ 
municates with the exhaust, for its outlet to the main port is closed 
just before the port opens for release, and is opened just after the 
port is closed for the exhaust. Its economy lies in its shoit travel. 
The double-ported marine slide-valve, shown in Fig. 192, is another 



























































240 


THE SLIDE-VALVE AND VALVE-GEAR 



Fig. 193.—Balanced 
slide-valve. 


novelty in the line of double ports. It is in use on marine engines 
on the intermediate and low-pressure 4 cylinders. 

The valve is shown in its middle position, in which all the ports 
are opened and closed alike and with but slight cut-off. The short 

travel required by double ports makes this type 
of valve desirable in the triple and quadruple 
engines. 

A type of balanced slide-valve much in use 
is shown in section in Fig. 193, consisting of a 
ring held in a recess at the back of the valve and 
pushed against the steam-chest cover by springs. 
The details of its construction vary somewhat in the different engines 
to which it is applied. The relief-press¬ 
ure varies from 60 to SO per cent. 

In Fig. 194 are shown the face and 
back of a balanced slide-valve and the 
steam-chest, with the valve in posi¬ 
tion as used on the Skinner high-speed 
engine. 

The valve has SO per cent, of its 
area relieved of pressure by a balance- 
ring which rides against the steam- 
chest cover. This ring is free to re¬ 
volve, and changes position with every 
stroke of the valve, preventing any 
creasing or cutting of seat, ring, or 
cover. Steam packing-rings prevent 
leakage between the ring and the hub of the valve. This construction 
allows a large port-area, which is necessary for proper steam-distribu¬ 
tion. Twenty per cent, of steam-pressure is sufficient to hold the 
valve in steam-tight contact with the seat and to take up the wear. 
The valve is free to lift from the seat in case water enters the cylinder. 



Fig. 194.—Balanced slide-valve, 
Skinner model. 


SLIDE -VALVES WITH A RIDING COVER 

Of this type of slide-valve there are many designs, with both 
single and double ports so arranged as to facilitate a full passage of 
steam with the shortest travel of the valve. In Fig. 195 is shown 



























































































TIIE SLIDE-VALVE AND VALVE-GEAR 


241 


a section of the cylinder and steam-chest of the Ames engine. The 
valve is a two-ported plate, one at each end, riding under a partially 
balanced pressure-plate, with recesses to allow of double-port openings 
and a short valve-travel. The supplementary port-opening is over 
each end of the valve-plate, as shown. This type is representative 
of a large number of engine slide-valves by different builders. 



Fig. 195. —Ames slide-valve. 



Fig. 196.—Chandler & Taylor double- 
ported slide-valve. 


In Fig. 196 is shown a section of the cylinder and steam-chest of 
the Chandler & Taylor engine 1 —a high-speed model designed with 
special adaptation for direct electric generator-connection. 

The valve-plate is two-ported at each end, a feature making it 
possible to give a large port-area with short valve-travel. This class 
of valves is so balanced and free to lift that there is little or no 
danger from slight excess of water in the cylinder. 


THE SLIDE-VALVE WITH INDEPENDENT 

CUT-OFF 

The most economical use of steam requires an earlier cut-off than 
can be obtained from the single D valve and a proper adjustment of 
the exhaust- and compression-lines. 

In order to obtain the short cut-off with the required conditions 
of exhaust and compression in the slide-valve, a number of devices 
have been proposed and used in Europe and the United States. 
Among such are the Gonzenbach, with a three-ported solid lidei in a 
separate steam-chest at the back of the regular D valve, the solid 
sliding valve on the back of the main valve, as designed b\ Hreval, 
























































































































242 


THE SLIDE-VALVE AND VALVE-GEAR 





Fig. 197.—Meyer expansion-valve. 



Polonceau, Napier & Rankin, Farcot, Borsig, A. K. Rider, and other 
models, most of which are used in locomotive service. 

The Meyer expansion-valve has proved its value for stationary 
service by its continued use for more than a half-century. In this 

valve the riding cut-off 
consists of two blocks 
adjusted for any re¬ 
quired cut-off by right- 
and left-handed screws 
on a traversing spindle, 
as shown in Fig. 197. 
A, A are the cut-off 

blocks adjusted by the right and left threads on the spindle B, which 
extends through both ends of the steam-chest, with a swivel at G, a 
wheel, H, for turning the spindle, and an index at i to designate the 
amount of cut-off; S is the half-travel of cut-off valve. At the right is 
a diagram of the eccentrics and crank-pin. The lap and lead of the 
main valve are not effected by the operation or adjustment of the 
cut-off valve. 

A novel arrangement of balanced valves with simultaneous move¬ 
ment for both cylinders of a compound tandem type, as used on the 


By-pass 

Valve 



Fig. 198.—Union valves, compound tandem engine. 


locomotives of the Pittsburg Locomotive Works, is shown in Fig. 198. 
The cylinders have a sleeve between the heads which carries the 
piston-rod without packing. 













































































































































































THE SLIDE-VALVE AND VALVE-GEAR 


243 


The valves are connected by a rod passing through a pipe between 
the steam-chests of the high-pressure and low-pressure cylinders. 
The high-pressure valve receives steam through the balance-plate, 
which is movable, with piston-rings for 
perfect closure. In ordinary use the ex¬ 
haust-steam from the high-pressure cylin¬ 
der passes through the pipe covering the 
connecting-rod to the steam-chest of the 
low-pressure cylinder. A by-pass valve 
and side port allow of turning high- 
pressure steam directly to the low-pressure 
cylinder when needed for starting. 

In Fig. 199 is shown a section of the 
cylinder and balanced valve of the Brownell engine. The valve is 
of the box type, double-ported for both steam and exhaust, and 
practically perfectly balanced. 

The steam-pressure is removed from the back by means of a balance¬ 
ring which bears against the steam-chest 
cover. A coil-spring serves to keep the ring 
against the chest-cover; thus taking up the 
wear automatically and preventing the ring 
from leaving its seat and causing annoy¬ 
ance by rattling. This class of balanced 
valves is in use on the Skinner, Ball & 
Wood, Payne, Erie, and other high-speed 
engines. 

A balanced valve of the Wilson type is 
shown in three positions in Fig. 200. The 
uppermost figure shows the opening posi¬ 
tion of the double port; the middle figure, 
the wide-open position, and the lowermost 
figure, the exhaust position. The gridiron 
form of the valve shortens the valve-travel 
and doubles the port-area. The exhaust- 
ports are also double in the action of this 
valve. The ported balance-plate rests un¬ 
der an adjusting-plate bolted to the steam-chest co’ser, which makes 
the valve almost frictionless. 





Fig. 200.—Wilson slide-valve. 



Fig. 199.—Brownell balanced 
slide-valve. 





























































































































































































244 


THE SLIDE-VALVE AND VALVE-GEAR 


In Fig. 201 is shown the balanced slide-valve of the Bayley vertical 



automatic engine. The pressure-plate is free from the steam-chest 
cover and pressed against the valve by a spring; it is held in place 
by adjustable stays against the ends of the steam-chest and by side- 
bars to prevent lateral motion. 

The oscillating cylindrical valve, shown in Fig. 202, is still much 
in use on hoisting-engines with cam, eccentric, or secondary crank- 
motion. It seems to be well adapted to the operation of hoist¬ 
ing and other small engines by the simplicity and direct action 
of its gear. Steam enters at the top of the cylinder at S and passes 
around the cylinder to the valve- 
chest at P, P—a means for keeping 
the cylinder clear of water while 


Fig. 201.—Bayley slide-valve. 


Fig. 202.—Oscillating valve. 


the hoist is waiting. The valve-arm V is directly connected to the 
crank-pin arm at E. These valves operate on the same principle as 
the plain slide-valve, with from five-eighths to three-quarters cut-off 
for light work, or full stroke for heavy, slow pull and two cylinders. 

The gridiron or multiported valve is much in use in the marine 
service and on the stationary engines of the Slater Engine Company, 
McIntosh A Seymour, the American A British Mfg. Co., and C. li. 
Brown & Co. 

In Fig. 203 is shown a cross-section of the cylinder of the McIntosh 
A Seymour engine, with the valve-gear of the steam, exhaust, and cut¬ 
off valves. The four valves, steam and exhaust, are operated from 
a rock-shaft at M, which in turn is rocked by a fixed eccentric through 
a bell-crank lever connected to a crank on the rock-shaft. The os¬ 
cillating pin P, on the rock-shaft wrist-plate at M, operates the exhaust- 

































































































THE SLIDE-VALVE AND VALVE-GEAR 


245 



Fig. 203.—Gridiron valves and cot-off. 


valve by a direct link and cross-head, c, while; the steam-valve is oper¬ 
ated from the pin l v through the link-rod S and toggle-joint me. 
The riding cut-oft valve is operated from a second rock-shaft located 
at A, with its variable motion controlled by the fly-wheel governor, 
which revolves the 
eccentric to advance 
the cut-off valve. The 
connection between 
the eccentric and 
rock-shaft is a bell- 
crank lever with a 
slipper - link bearing 
on the eccentric from 
one arm and a link to 
a crank-pin on the 
rocker-shaft. 

The connection between the rocker-shaft and the cut-off valve is 
shown in the figure at the right by a rocker-arm at A, linked to a 
bell-crank rocker pivoted at a, so arranged that the cut-off valve 
moves in the opposite direction to the main valve, and with the rapid 
closing of the ports giving a sharp comer on a card at the end of the 
admission-line. 

In Fig. 204 is shown an enlarged section of the gridiron valve and 
riding cut-off grid of the McIntosh & Seymour engine. 

In Fig. 205 is shown 
a section of the steam 
and exhaust gridiron 
valves and valve-gear 
of the Brown engine, 
and in Fig. 206 the 
motion - gear of the 
exhaust - valve. The 


TRAVEL 



STEAM GRID 


Fig. 204.—Section of gridiron valve and cut-off. 


vertically operated steam-valves and steam-chest are on the side of 
the cylinder, while the exhaust-valves are horizontal and beneath the 
cylinder. 

The operation of these valves may be understood from the cuts 
and reference-letters. 

The lifter A, which is connected to the lower arm of the bell-crank 




























































































246 


THE SLIDE-VALVE AND VALVE-GEAR 


lever B, lias just engaged the latch C, which is journalled on a pin on the 
guide D. When the long arm B is drawn toward the crank-shaft by 
the eccentric, the lifter A is raised, which carries the latch and guide up 
with it and causes the valves to open the ports. This upward move¬ 
ment continues until the outer end of the latch engages the trip-lever 
E, which causes the latch to let go of the lifter, when the valve im¬ 
mediately descends, dropping by its own weight, and being cushioned 
by the dash-pot directly under the guide, which movement closes the 
ports and effects the cut-off, which, owing to the short travel of the 



Fig. 205.—Gridiron valves, Brown engine. Fig. 206.—Exhaust valve-gear. 


valve, is very sharp, permitting no wire-drawing of the steam. The 
trip-lever E is carried by the auxiliary shaft G, which is connected 
to and is actuated by the governor. 

The exhaust-valve mechanism is shown in Fig. 206, which repre¬ 
sents a plan. The exhaust-valves have a positive connection with the 
sliding bar A, and hence have an unvarying travel. 

When the sliding bar A is moved to the right in the cut by the 
exhaust-eccentric, the longer arm C of the exhaust-lever is moved 
inward, while the shorter arm is moved outward, which opens the 
exhaust-ports, the reverse movement taking place when the port is 
closed. 


























































































































THE SLIDE-VALVE AND VALVE-GEAR 


247 


THE DIAGRAM OF THE SLIDE-VALVE FOR 

CUT-OFF 

The lay-out of a slide-valve diagram is an easy matter when once 
we consider its simple intricacies. Assuming that the lap is required 
and that the lead is prefixed to some definite amount between the 
usual variation from to T 3 g- inch or more; the lead in any case 
being kept as small as possible to allow the admission-line on the 
indicator-diagram to be vertical; to find the lap and lead. 

A diagram for cutting off at three-quarters stroke is shown in Fig. 
207, on a scale in parts of the engine-stroke, say for 12 inch, as 
shown in the diagram, 
for 12-inch stroke. 

In this diagram the 
connecting-rod angle is 
not considered, but 
should be allowed for in 
precise work, as shown 
in the foregoing chapter. 

On the 12-inch base¬ 
line of the semicircle 
ABB measure the dis¬ 
tance of the piston from 
A equal to the cut-off, say 9 inches, and from this point draw a verti¬ 
cal line to the semicircle at K; draw the line from the centre 0 to K, 
and the line Mn, at a distance from AB, equal to the lead, say T V 
inch. Iv is the position of the crank-pin at three-quarters stroke. 

Next find the centre of a circle on the semicircle described by the 
centre of the eccentric, and describe the circle EFG, with its circum¬ 
ference tangent to the lines M n and OK, as at F and G. 

The radius of this circle will be the required lap to be added to 
the valve in order that it may cut off at three-quarters of the stroke. 
The amount of lap to be added for this point of cut-off is inch. 

The diagram will also show the amount the port-opening has been 
decreased after adding lap to the valve. With 0 as a centre and the 
compass-pen open to a length equal to the distance OF, describe an 
arc of a circle that will be tangent to the lap-circle at F, and the 



Fig. 207. —Lap- and lead-diagram, three-quarters 

cut-off. 





























248 


THE SLIDE-VALVE AND VALVE-GEAR 



distance OE is the amount the port will be opened when the eccentric 
is at its greatest throw, which in this case is 1 T V inches. 

By adding lap to the valve we have also changed the position of the 

centre of theeccentric. 

Instead of being in 
a position of 90 de¬ 
grees ahead of the 
crank, it must now be 
moved a considerable 
distance beyond this 
point and equal to the 
distance BP, or 31 de¬ 
grees, or 121 degrees 
ahead of the crank. 



Fig. 208.—Lap- and lead-diagram, five-eighths cut-off. 


In Fig. 208 is shown a diagram for five-eighths cut-off, with lead as 
before and lap of l T y inches, as shown, the port-opening being reduced 
to yf inch and the angle of advance being increased to 41-y degrees, 
the total advance be- K 

ing 131y degrees. 

Fig. 209 shows a 
diagram by which any 
position of the valve- 
gear and the different 
positions of the valve 
may be found when 
some of the other 
events are known. 

Suppose we know the 
valve-travel, the lap, 
and lead, and want to 
know what the cut-off 
and angle of advance 
will be. With the 
point 0 as a centre, 
and a radius equal to 
the length of the crank, describe the circle ARB. The diagram 
should be drawn to some scale, say 3 or 6 inches to the foot. The 
diameter AB of the circle will represent the stroke of the engine, 

























































THE SLIDE-VALVE AND VALVE-GEAIl 


249 


and the circle itself will represent the path of the centre of the 
crank-pin for one revolution. 

Again, using O as a centre and a radius OD, equal to one-half 
travel of the valve, describe the semicircle CFD. The diameter CD 
will represent the travel of the valve. 

Above and parallel to the line AB draw the line MN, a distance 
from AB equal to the known lead. 

Draw also the line HJ parallel to the line MN, and a distance 
above it equal to the known lap. 

The line IiJ will intersect the semicircle CFD at I, and with I 
as a centre and a radius equal to the distance IG, which is the re¬ 
quired lap, describe the circle FEG. 

From the centre 0 draw a diagonal line that will be tangent to 
this circle at F and will intersect the large circle at K. 

Next draw the diagonal line from the centre 0 and through I of 
the lap-circle, and intersect the large circumference at P. K will be 
the position of the crank-pin, and L will be the position of the piston 
in the cylinder when the steam is cut off. The angle BOP will be 
the required angle of advance. 

Take another case, where we know the valve-travel, the angle of 
advance, and the cut-off, and we want to know the amount of lap 
and lead. Lay off the stroke the same as before, and draw the cir¬ 
cumference described by the centre of the crank-pin, and suppose the 
piston and crank-pin to be in the same positions as before, at L and 

K. Draw the perpendicular line LK, and from the centre 0 draw 
the line OK. From B lay off the angle of advance, BOP. The line 
OP will intersect the semicircle at I. With I as a centre, draw a 
circle that will be tangent to the line OK, as at F. Draw the line 
MN, tangent to the circle just described and parallel to the line 

AB, and the distance between the lines AB and MN is the required 
lead, and the radius IG will be the required lap. 

Take another case, where we know the lap and lead and point 
of cut-off, and wish to find the valve-travel and angle of advance. 
Proceed the same as in the previous cases, and locate the points K 
and L and also draw the line MN. Open the compass to the required 
lap and find by trial the centre I, from which a circle may be described 
tangent to the lines OK and MN, as at F and G. 

Next, with 01 as a radius and 0 as a centre, describe the semi- 


250 


THE SLIDE-VALVE AND VALVE-GEAll 


circle CID, passing through I. The distance CD will be the travel 
of the valve. From 0 and through the centre I draw the line OP, 
and BOP will be the required angle of advance. 

There is still one other case where this diagram can be used, 
where we know the point of cut-off, the lead, and the amount of 
port-opening when the valve is at the end of its travel, and we wish 
to find the lap, the valve-travel, and angle.of advance. 

The crank-pin and pistons are supposed to be in the same positions 
as in the previous cases, and the cut-off is also supposed to be the same. 

Draw the lines OK and MN, and with 0 as a centre and a radius 
OE equal to the known port-opening, describe an arc of a circle. 
Next, by trial find the centre I of a circle, which, when described, 
will be tangent to the arc just drawn, and which will also be tangent 
to the lines OK and MN, as at F and G. 

The radius of the circle will be the required lap. From 0 draw 
the line OP, and the distance BP will be the angle of advance. 
Through I draw a semicircle with a radius equal to 01. The diam¬ 
eter CD of this semicircle will be the distance travelled by the valve. 
In all of the above cases the radius OE represents the amount the 
port will be opened when the eccentric is on its dead-centre or at 
the position D. Notice also that the crank is supposed to be on the 
dead-centre at A, and that the engine is about to make the forward 
stroke. This makes it necessary to lay off the whole geometrical con¬ 
struction to the right of the centre 0. 

The measurements foi the other stroke, with the engine on the 
dead-centre at B, will have to be constructed to the left of the centre 
0 and below the line AB. The measurements for this stroke will 
be theoretically the same, and are shown by the dotted lines. 

We could use the same diagram to lay out the movements for a 
piston-valve. A piston-valve, to cut off at the same point of the 
stroke, would require the same amount of lap; and if the nature of 
the work done by the engine was the same, it would require the same 
amount of lead. 

A valve is said to be direct when it admits the steam to the cyl¬ 
inder past its outside edge, and allows the steam to exhaust to the 
atmosphere past its inside edge. A valve is said to be indirect when 
it admits the steam to the cylinder past its inside edge, and allows 
the exhaust-steam to escape past its outside edge. 


THE SLIDE-VALVE AND VALVE-GEAR 


251 


These are the conditions of a piston-valve whose movement is just- 
opposite to that of a slide-valve. Another thing to be noticed is the 
difference in the movement of the two valves relative to the move¬ 
ment ot the piston. When the opening movement of the slide-valve 
occurs the valve and the piston both move in the same direction. 

With the opening movement of a piston-valve the valve and 
piston move in opposite directions to one another. This makes it 
necessary to shift the centre of the eccentric to a position exactly 
opposite to that of a slide-valve. 

THE PISTON-VALVE 

The use of the piston-valve has been largely extended of late years 
by its advantages over the slide-valve in the accessibility of its parts, 
lightness, more perfect balance, and greater port-area, which features 
make it easier to handle, and decrease the wear and tear on the motion- 
work of an engine. With the increased size of engines and steam- 
pressure the ordinary D balance-valve increases in size proportion¬ 
ately, and while we may balance a slide-valve in the same ratio as the 
valves on smaller engines, the difference in the unbalanced surface 
increases with the size of the engine, and with it the wear on the 
valve, link-motion, and eccentric-straps, and the work necessary 
on the part of the engineer to handle the engine. This being a fact, 
a great deal of trouble is experienced in keeping the valves on slide- 
valve engines true to their seats, while on the other hand there is 
no trouble of this kind with the piston-valve until after the engine has 
been in use for a long while and the 
parts have become badly worn. The use 
of the inside admission piston-valve does 
away with the metallic valve-stem pack¬ 
ing, which means a great saving, as there 
is only the exhaust-pressure on the pack¬ 
ing side, and the fibrous packing answers 
the purpose and lasts a long while. 

A simple piston-valve taking steam 
at its ends and by a passage through 
the valve is used on the Noye engines, and shown in Fig. 210. The 
valve has a long middle bearing and rides in a ported sleeve, forced 



Fig. 210.—Noye piston-valve. 














































252 


THE SLIDE-VALVE AND VALVE-GEAR 


into the cylinder of which die steam-chest forms a solid part. The 
exhaust-ports are double, thus giving a long bearing to the valve. 
The valve-rod is connected direct to the eccentric and its rod by a ball- 
and-socket joint to correct any irregularity in the alignment. 

Fig. 211 is a section of a simple hollow piston-valve, the rod of 
which passes through a central tube with bar-stays to the valve and a 
lining to the valve-chest. It can take steam at the centre or ends, as 
convenient, and operates exactly as a D slide-valve, with three times 
its extension of port-opening; hence short ports and valve-travel. 



Fig. 211.—Hollow piston- Fig. 212.—Armington & Sims double¬ 
valve. ported piston-valve. 


A double-ported piston-valve in use on the Armington & Sims 
engines is shown in section in Fig. 212. In this model the steam 
enters the steam-chest between the valve-pistons. It will be seen 
that steam-admission is through two ports at A and B in the valve 
and at both ends simultaneously. The steam entering at port B 

passes through the hollow neck of the 
valve, thus duplicating the port-open¬ 
ing for a short travel of the valve. For 
the exhaust the valve is single-ported, 
but the great width, due to its cylin¬ 
drical form, gives ample port-opening 
with a short travel of the valve. 

In Fig. 213 is shown a section of 
the piston-valve chest and the valve 
used on the Harrisburg engine. The 
pistons of the valve are separate from 
the rod, though fastened to it and 
made adjustable by nuts and lock-nuts. It takes steam at the cen¬ 
tre and exhausts from steam-chest ports outside the valve-disks. It 
ha« the same conditions as to lap and lead as the plain slide-valve, 



Fig. 213.—Harrisburg piston- 
valve. 





















































































































































































THE SLIDE-VALVE AND VALVE-GEAR 


253 


but v ith the advantage that lap, both outside and inside, may be 
increased by changing or separating the parts of the disks with a 
washer-disk of any required thickness. 


THE SLIDE-VALVE GEAR AGE AND GOVERNORS 

The plain slide-valve gear, as illustrated on page 225, is greatly 
modified and complicated for the various purposes of adjustment to 
suit the needed requirement for speed and reversing, and also for 
obtaining the valve-motion 
without the eccentric. 

The link - motion from 
double eccentrics, much in use 
on marine engines and loco¬ 
motives, is shown in Fig. 214. 

It has been long known as the 
Stephenson link. In this plan 
the slotted link is moved up 
or down for shifting the valve-motion or for reversing by a lever and 
connecting-rod. Its design has many forms to suit the varying con¬ 
ditions of this plan of link-motion, as shown in Fig. 215, and is largely 
in use in its simplest form on the engines of the smaller marine craft, 

from the pleasure-boat to the tug¬ 
boat, and on steam-driven automo¬ 
biles and traction-engines. This link- 
motion is used in connection with 
ordinary D or gridiron valves, with 
the usual lap and lead for from five- 
eighths to three-quarters cut-off. 

A reversing link-motion from a 
single eccentric is shown in Fig. 216, 
in which the slotted link is pivoted to 
the end of the eccentric-rod and is 
moved up and down by a bell-crank 
lever. The block carrying the valve- 
rod is stationary,.allowing the pivoted 
link-centre to pass by it and thus 
reverse the valve-motion. There are 




Fig. 215.—Link on vertical engine. 




























































254 


THE SLIDE-VALVE AND VALVE-GEAR 


a number of curious models of valve-motion from single eccentrics, 
of which we select the following as examples of design in this 
interesting line. 

A method of lengthening the stroke of an eccentric of small size 
by a link-connection to the eccentric-strap at a right angle with the 



Fig. 216.—Single-eccentric reversing- 
gear. 


Fig. 217.—Method of increasing 
eccentric. 


connecting-rod is shown in Fig. 217. In this way a considerable 
increase in the throw of the eccentric can be made, depending upon 
the relative lengths of strap-arms. A variable and adjustable throw 
of a single eccentric—called the Fink link-gear—for a D valve is shown 
in Fig. 218. A curved slot-link is made a fixture of the eccentric- 
strap, as shown, one end of which is pivoted to a swinging link 
attached to the engine-frame. The end of the jointed valve-rod is 
pivoted to a block in the link, and its distance regulated by a con¬ 
necting-rod and screw pivoted to the valve-rod near the link. 



Fig. 218.—Direct variable valve-motion. Fig. 219.—Variable link valve-motion. 

Another and simple lever and link-movement for variable expan¬ 
sion from a single eccentric is shown in Fig. 219. The lever is pivoted 
to the connecting-rod of the eccentric and travels past the fixed pivot 

















































THE SLIDE-VALVE AND VALVE-GEAR 


255 


of its link, thus swinging the end of the eccentric-rod up and down 
for the valve-motion. The position of the upper end of the lever is 
adjusted by a wheel and screw for varying the throw of the valve. 
Many variations of this idea have been pro¬ 
posed and used. 

Another design of past usage which is 
illustrated in Fig. 220, represents but one of 
the many strenuous efforts to utilize the sin¬ 
gle eccentric for the most efficient and eco¬ 
nomical work of the valve. Here the end of 
the eccentric-rod is pivoted to a block in a 
slotted link that by tilting up or down with 
a screw varies the throw of the valve, the 
valve-rod being pivoted to the eccentric-rod. 

The Marshall valve-gear, shown in Fig. 

221, is operated on the same general princi¬ 
ples as the last two examples. A single eccentric, set opposite to 
the crank and its short connecting-rod, is pivoted to the valve-rod 
at J, with its end pivoted to a link, GF, which is also pivoted to a 
bell-crank lever at G, whose length', GH, is the same as that of the 



Fig. 220.—Block-link varia¬ 
ble valve-motion. 



Fig. 221.—Marshall valve-gear. 


link GF. The other end of the bell-crank lever is pivoted to the rod 
K and to a hand-gear for throwing over the bell-crank link to the 
position at G' for reversing the engine, and to intermediate points 
between G and G' for varying the cut-off. This gear gives a constant 
lead for both positions. The position of the gear in the cut is for run¬ 
ning “over.” 








































256 


THE SLIDE-VALVE AND VALVE-GEAR 


VALVE- G E A It S W I T H O U T E CCEN T RIGS 


The idea of operating a steam-engine without an eccentric has been 
a theme of invention for a long time, and we illustrate those that have 
been in actual use and made a name for themselves—the Walschaert 
crank-pin arm and the Joy valve-gear. 

One of the Walschaert valve-gears, which uses an eccentric, but 
modifies its link-movement by a cross-head link and lever for making 

the lead, is shown in Fig. 222. The ec¬ 
centric-rod is pivoted to the lower end 
of a curved slotted link, itself pivoted at 
its centre to a fixed lug on the engine- 
frame. A bell-crank lever governs the 

position of the end of the valve-rod and 

Fig. 222. V alschaert valve-gear s pjj n g bl 0C L i n the link. An arm 
with eccentric. , 

Irom the cross-head is linked to a lever 
connected with the valve-rod and valve-stem for controlling the lead. 

Another model of this valve-movement, as used on the compound 
locomotives of the Italian railways, is shown in Fig. 223. The crank- 
pin arm operates the motion of the slotted link. The valve-rod block 
and the rod are balanced by a weight on the rock-shaft arm and 
operated by a lever connected to the third arm. Valve-lead is made 
by the cross-head arm-link and lever connected to the valve-rod and 
link-block rod. 




A novel r ever sing-gear without eccentrics is shown in Fig. 224. 
The valve-stem is connected to the middle of a short link, one end 
of which are pivoted to the cross-head bar or swinging-lever sliding in 
an eye or sleeve-block on the cross-head; the opposite end of the 











































































THE SLIDE-VALVE AND VALVE-GEAR 


257 



link is pivoted to a radial bar and to the slide on the link-block, 
this block receives a vertical motion from a sliding-block on the 
connecting-rod, which is kept in position by a rod pivoted on the 
cylinder - head. The 
cross-head swinging- 
bar imparts a move¬ 
ment to the valve- 
stem equal to the lap 
and lead of the valve. 

The lateral motion 
of the connecting-rod 
operates the throw 

and reversal of the valve by the position of the sliding-link as con¬ 
trolled by a hand-lever. 

A floating valve-gear, used on the reversing-ram of large marine 
engines, and having peculiar features in its movement, is shown in two 
positions in Fig. 225. The floating-lever g is connected to the cross¬ 
head at k, and pivoted to the valve-rod at h and to the reverse- 
lever rod at i. The piston-valve is indirect, and takes steam at its 
centre. When the lever d is set vertical the action of the valve sends 

the piston to the centre of the cylin¬ 
der, and when pushed over sends the 
piston in the opposite direction. The 
springs at each end of the traverse-bar 
are to prevent shock by the sudden 
movement of the piston. 

A novel valve-gear has been ap¬ 
plied to a three-cylinder engine, illus¬ 
trated in Fig. 226, in which the piston- 
valves are operated by a connecting- 
rod from the valve to the trunk of the 
following piston. The exhaust is dis¬ 
charged into the main trunk of the en¬ 
gine through the hollow spool-valves, 
and from the ports opened by the 
trunk-pistons into jacketed recesses. Steam-connection is made with 
the chambers at the head of each cylinder. 

Another curious engine is the "Brotherhood’’ three-cylinder 









































































































































258 


THE SLIDE-VALVE AND VALVE-GEAR 


engine, of English origin, in which the steam enters and fills the 
central chamber with equal pressure on all the pistons. The valve 
is of the rotary-disk type, operated by the crank-pin within the 


Fig. 226.—Three-cylinder engine. 



chamber, and gives steam to the outside of the pistons alter¬ 
nately through an outside port to each cylinder. The steam-passages 
cover the shaft, making a steam-tight stuffing-box necessary on the 
shaft. Its advantages are compactness and convenience for small 
powers, but it lacks efficiency. 



Fig. 227.—“ Brotherhood” type 
of three-cylinder engine. 


Fig. 228.—Wolf reversing-gear. 


In regard to the various types of rotary engines and the hundreds 
of different models and valve-gear motions which have passed the or¬ 
deal of trial and failure, we can only say, from our own experience and 
knowledge of their temporary life, that the rotary principle, as de¬ 
veloped in its long career, has finally found its success only by going 




































































































THE SLIDE-VALVE AND VALVE-GEAR 


259 

back to the type of the early ages—the simple reaction of the Hero 
and Avery models—with the addition of the multiple effect, and cul¬ 
minating in the modern steam-turbine. 

The reverse-gear of the Wolf model is another form for reversing 
from a single eccentric, and is shown in Fig. 228. 

The end of the eccentric-arm B is pivoted to a block in the slotted 
link S, which is also shown in its opposite position for reversing at S'; 
the valve-rod R, being connected by a pivot to the eccentric-arm 
at a, acquires an elliptical motion by the action of the eccentric and 
the link-block, which becomes 
vertical or reversed by throwing 
over the link. 

A most novel valve-gear for 
a triple-expansion engine from a 
single eccentric is used on the 
engines of the Edison Electric 
Company, New York City, and is 
illustrated in Fig. 229. The eccen¬ 
tric-arm is pivoted by a link-arm 
to the frame at A, which carries a 
pin off from its central line, and 
connects with the high-pressure 
valve-rod. The bell-crank lever 
B is pivoted by a link to the 
lower side of the eccentric-strap, 
and from its upper arm is pivoted 
to the mean-pressure cylinder 
valve-rod; the low-pressure valve-rod is a direct-line connection 
through a rocker-shaft and arms at C. This is the most ideal con¬ 
ception for operating the valves of a triple-expansion engine yet 
brought to the notice of the author. It is a study for the curious in 
valve-gear motion. 

A valve-gear derived from the elliptical motion of a pin near the 
middle of the connecting-rod is the ideal of the “Joy” valve-gear 
movement. The ellipse made by the path of the pin is symmetrical 
with the central line of motion in the engine; but the action of the 
link-movement slightly changes the direction of its axis in regard to 



Fig. 229.—Triple-expansion valve-gear. 









260 


THE SLIDE-VALVE AND VALVE-GEAR 


the valve-motion. Its application to a vertical engine is shown in 
Fig. 230, with a screw-adjustment for the position of the link. 

In Fig. 231 is shown the same arrange¬ 
ment applied to a horizontal engine, with 
a connecting-rod, A, extending to a lever 
for reversal. 




Fig. 230.—Vertical valve-sear, 


Fig. 231.—Horizontal valve-gear, 


!X 


In Fig. 232 are given a more defined diagram and description of 
the Joy valve-gear. 

The end of the lever abc is guided by the rod gc, and is attached 

to the connecting-rod at a point, a, 
which describes an ellipse, having the 
length aici 2 equal to the stroke of the 
piston. This ellipse, which is omitted 
to avoid confusion, is symmetrical with 
regard to the axis XX', and is slightly 
more pointed at the crosshead-end than 
at the crank-end. 

The point b, which describes the 
irregular ellipse bbib 2 , takes the place 
of the single eccentric used on other 
valve-gears, and acts on the lever hi, 
while e is guided on the circular arc //1 
by the sliding-block B, and the point e , 
which describes the ellipse ee x e 2% carries 
the valve-rod ed. The connecting-rod 
CD, the valve-rod ed, and the rod eg 
are in the same plane; the levers ac and 
be and the curved guide-bars //1 are 
double, one set of levers being on 
each side of the connecting-rod. In the 













































THE SLIDE-VALVE AND VALVE-GEAR 


261 


drawing the system of levers in front of the connecting-rod is omitted 
to show the construction more clearly. The point i could be guided 
on the arc //1 by a link centred at e. Such a construction is used in 
marine engines. 

The radius of the guiding-link jj\ is always equal to the length 
of the valve-rod. 

The irregularity due to the angularity of the lever hie is com¬ 
pensated for by the action of the lever ac, somewhat in the manner 
that the linkage known as Watts’s parallel motion is made to give 
nearly a straight line of motion. 

The guiding-bars //1 are hung on trunnions, with the axis at the 
point ii, and are connected at / to the reversing-lever. The gear is 
shown in full-gear position for left-hand rotation. It may give a 
shorter cut-off if the guiding-bars //i are given less inclination from 
the horizontal or mid-gear position, and when in mid-gear it will give 
the valve a motion equal to the lap plus the lead; and when the 
guiding-bars //i are inclined the other way, the engine will be reversed. 

When properly proportioned the Joy gear gives rapid motion to 
the valve when opening and closing, less compression at short cut-off 
than does the link-motion, and the cut-off can be made nearly equal 
for all positions of the gear. Like many other valve-gears, it gives 
constant lead. The principal defects are the number of parts and 
joints that are liable to wear loose, and the obstruction that it offers 
to inspection and to proper care of the crank-pin and cross-head 
when the engine is running. 

In Fig. 233 are shown the plan and vertical section of the Porter- 
Alien medium to high-speed engines, made by the Southwark Foundry 
and Machine Company. The valve-gear, which is of the four-port, 
balanced slide-valve type, is of peculiar interest, not only in the fact 
of having four slide-valves, but in the way in which the transmission 
of motion to the valves from a single eccentric is made. The steam- 
and exhaust-valves are on opposite sides of the cylinder, and are 
operated from a single eccentric through independent rock-shafts. 

The movement of each valve opens or closes double-port passages 
for steam and exhaust, as shown by the arrows in Fig. 234. By this 
construction only narrow seats and short valve-strokes are required 
to give large port-openings. The arrangement of the valve-gear is 
clearly shown in plan and elevation in Fig. 233. The eccentric E is 


i 



ELEVATION 

262 Fig. 233.—Plan and elevation of the Porter-Alien engine. 





































































































































































THE SLIDE-VALVE AND VALVE-GEAR 


263 


forged on the shaft and is coincident with the crank. The eccentric- 
strap and the curved link L are made in one piece, and the link is 
pivoted at its central point on the trunnions t, which in turn are pivoted 
to the frame at the fixed point A. The vibration or horizontal move¬ 
ment of the trunnions is equal to the throw of the eccentric. In the 
slot of the link is the block B, from which are driven the two steam- 
valves. The short rock-shaft s on the frame is actuated by the outer 
arm a, which is connected by the steam-rod with the block in the link. 
It carries on its inner end the two arms H and C, which drive respec¬ 
tively the head-end and crank-end steam-valves, through the medium 
of the two rods h and c, and the two valve-stems. The steam-valves 
are offset in the chest, in order that connection to each valve may be 
made at its centre; and short guides are provided at the connections 
of the rods H and C and the valve-stems. 

An inspection will show that the link has a peculiar movement, 
composed of the horizontal and vertical throws of the eccentric. 
The link is restrained from rising by the trunnions, and the horizontal 
throw of the eccentric draws off the lap of the valve, while the vertical 
throw tips the top of the link alternately to and from the cylinder as 
the eccentric-centre rises or falls in its-revolution, the upward throw 
tipping the link toward the cylinder and the downward throw tipping 
it from the cylinder. 

This tipping of the link 
opens and closes the 
steam-valves by rock¬ 
ing the rock-shaft by 
means of the steam-rod 
and arm a. 

In Fig. 234 is shown 
a horizontal-plan sec¬ 
tion of the cylinder and 
steam-chests, with the 
double port-opening 
for both steam and exhaust at the commencement of the forward 
stroke. The valves are opened and closed quickly by the middle move¬ 
ment of their arms, and have very little movement while open or closed, 
as the arms are then at the extremes of the travel. The position ol 
the block in the link is under the control of the governor, a dropping 




Steam Chest 

yy :■'s///////////y////////zvJZZ: 


Fig. 234.—Porter-Alien cylinder. 
























































































Fig. 235.—High-speed tandem compound engine, manufactured by the Ball Engine Company. 





















































































































































































































































































































































































































































266 


THE SLIDE-VALVE AND VALVE-GEAR 


of speed causing the governor-balls to drop and so raise the block, and 
an increase of speed forcing the block down toward the trunnions. 
When the block is at the top of the link, the steam-rod receives the 
full tipping motion of the link, and cut-off takes place at the maximum 
point, about six-tenths of the stroke. On the other hand, when the 
governor-balls are in the extreme upper position the block is forced 
clear down to the trunnions, and so receives none of the tipping 
motion of the link. Then the valve is merely opened for lead, and is 
closed immediately. 

Thus the steam-valves are always opened and closed quickly at 
the mid-travel of their arms; the velocity of cut-off increases as the 
cut-off is lengthened, since the block is higher in the link, and so cor¬ 
responds to the increased piston-velocity near mid-stroke; and the 
velocity of valve-movement is increased directly with the speed of the 
engine. 

The Porter fly-ball governor is used. It is carried on a bracket 
from the engine-frame and is belted to the crank-shaft. Its distinguish¬ 
ing features are light fly-balls with a high rotative speed to secure 
sensitiveness, and a heavy ball or weight on the vertical shaft to secure 
the gravity-effect required to keep the revolving balls in their effective 
plane. 

Figs. 235 and 236 give sketches of the plan and sectional elevation 
of a high-speed tandem compound engine direct connected to a multi¬ 
polar generator. The slide-valves of both cylinders are operated from 
a single eccentric with a rocker-arm and valve-rod extension through 
the low-pressure steam-chest, on the end of which is an arm attached 
to the high-pressure valve-rod, with adjustment for its proper opera¬ 
tion. 

The receiver is simply a pipe-connection from the exhaust of the 
high-pressure cylinder to the steam-chest of the low-pressure cylinder. 
The cylinder-volumes are so proportioned that the assigned cut-off 
in the high-pressure cylinder will equalize the gross pressures in both 
cylinders for the required speed. 


CHAPTER XVI 


THE CORLISS ENGINE 

In Fig. 237 is shown a full-page view of the Corliss engine, with 
single eccentric and the usual transmission-gear for operating the 
valves, and with the names of the various connections, the details of 
which will be illustrated in the following pages. 

The eccentric, by means of the eccentric-rod, rocker-arm, and 
reach-rod, causes the wrist-plate to oscillate back and forth. On the 
wrist-plate are placed the steam- and exhaust-pins which operate the 
steam- and exhaust-links respectively. These links operate arms at¬ 
tached to the valves. The exhaust-valves are attached directly to the 
exhaust-arms, and they rock back and forth with the wrist-plate, 
opening and closing the exhaust-ports at the proper time. The 
steam-valves are operated differently.’ Each steam-link oscillates a 
bell-crank, which is loose on the steam-valve stem. On this bell-crank 
is a latching-gear, which is arranged to take hold of a steam-arm 
directly attached to the steam-valve. As the bell-crank moves, the 
steam-valve is thus made to follow it, and thereby open the steam-port. 

As the latch on the bell-crank moves, it reaches a stationary knock¬ 
off cam, and the further motion of the bell-crank forces the latch 
against this cam, so that the latch is released and the bell-crank can 
no longer pull the steam-arm with it. The steam-arm is always acted 
upon by a downward pull from the dash-pot. Hence, as soon as the 

knock-off cam causes the latch to release, the steam-valve is pulled 

_ • 

shut by the dash-pot and cut-off occurs. The position of the knock¬ 
off cam is changed by the governor, so that the time of cut-off varies 
with the load on the engine, in order to keep the speed constant. 

The figure shows the eccentric in the lower central position—that 

is, with the eccentric vertically downward. Each point on the wrist- 

plate is then in the centre of its motion. Arrows indicate the directions 

in which the various parts are moving. The piston has very nearly 

reached the crank-end of its stroke, and the crank-end steam-valve 

267 





268 Fig. 237.—General arrangement of the Corliss valve-gear. 












































































































































THE CORLISS ENGINE 


269 


is almost ready to open, in order to admit steam to drive the piston on 
the backward stroke. 

The amount by which the crank-end steam- yalve closes the port 
in the position shown is the steam-lap. The head-end steam-valve 
was pulled shut by the dash-pot some time before the position 
shown. The bell-crank then moved to the end of its travel bv 
itself, and it is now going back again after the steam-valve in order 
to pick it up and cause it to open the head-end steam-port at the 
proper time. 

Since the wrist-plate is in the centre of its motion in the position 
shown, the crank-end exhaust-valve is in the same situation as is 
shown for the head-end exhaust-valve, but it is moving in the opposite 
direction with respect to its port, and is therefore just closing after 
having caused compression. The amount by which the exhaust- 
valves close the ports in the position shown is called the exhaust-lap. 

Each of the valves moves back and forth as the eccentric moves 
back and forth, exactly as would be the case with the various edges 
of a common slide-valve. There is a distorting effect due to the ob¬ 
liquity of the links in the Corliss gear, but this merely varies the speed 
with which the valves move. Therefore admission, release, and com¬ 
pression are effected by the eccentric in very much the same way 
with a Corliss valve-gear as with a common slide-valve. 

In all descriptions of the action of the common slide-valve will be 
found reasons for the use of lap and of angle of advance. For the 
same reasons, a Corliss valve has lap and angle of advance. The 
lap of a slide-valve is the amount by which the valve closes the port 
when both eccentric and valve are in their central positions. The 
lap of a Corliss valve is the amount by which the valve closes the port 
when the eccentric and wrist-plate are in their central positions. 
However, the valve itself is not then in the centre of its travel, owing 
to the distorting effect of the motion of the link and wrist-plate. 

The eccentric of a Corliss engine is therefore placed ahead of the 
crank by 90 degrees plus an angle of advance. In Fig. 237 the angle of 
advance is the angle between the crank and the horizontal centre line. 
The latest point of cut-off is somewhat less than half-stroke. The 
less the angle of advance the nearer it is to half-stroke. Hence, in 
order to increase the capacity of the engine, the angle of advance is 
made as small as possible. This is done by making the percentages 


270 


THE CORLISS ENGINE 


of compression and release as great as possible, since the angle of 
advance is determined by a point half-way between the two. 

The compression must occur early enough to give a proper cushion. 
It varies from 90 to 98 per cent., according to circumstances. The 
release must occur early enough to give a proper exhaust-lead. The 
exhaust-lead is the amount that the exhaust-valve is open when the 
piston starts on the exhaust-stroke. If the exhaust-lead is insufficient, 
the exhaust will be restricted at the beginning of the exhaust-stroke, 
giving an indicator-diagram with “turned-up toes.’ 7 On the other 
hand, a too early release must be avoided; otherwise the end of the 

expansion-line will be 
lowered. It will usual¬ 
ly be found that if re¬ 
lease occurs at from 98 
to 99 per cent, of the 
stroke, the exhaust- 
lead will be sufficient. 





Fig. 238.—Corliss valves. 


The details of the 
valves and valve-gear 
of the Corliss type are 
variable to a great de¬ 
gree, and we can only illustrate a few of the leading lines of design. 
In Fig. 238 are shown two forms of steam-valves and one of the 
exhaust-valve in general use with a single eccentric. The stem of the 
uppermost valve is mortised vertically into the valve, which gives 
the valve a free adjustment for perfect seating. The stem in 
the middle figure passes entirely through the valve with rectangular 
bearings, while the stem of the 
exhaust-valve works in a horizon¬ 
tal mortise. 

In Fig. 239 are shown sections 
of the double-ported steam- and 
exhaust-valves and their action, 
as shown by the arrows. This 
model of valve is operated by 
double eccentrics and double wrist-plates, which allows a greater range 
of cut-off than practicable with a single eccentric and single wrist-plate. 




Fig. 239— Double-ported Corliss valves. 












































































THE CORLISS ENGINE 


271 


The single eccentric and single wrist-plate allow of the proper 
opening and closing of the steam- and exhaust-ports with regard to 
cut-off, exhaust, and compression for a cut-off not later than one-half 
to five-eighths of the stroke, while the double eccentric and double 
wrist-plate give a possible cut-off at nearly full stroke in case of 
overload on the engine. 

In Fig. 240 is shown a single-eccentric valve-gear with overpull 
steam- and exhaust-links, as well as the right- and left-threaded 



adjustment-couplings and lock-nuts, and in Fig. 241 a double eccen¬ 
tric valve-gear on a single centre with overpull steam- and exhaust- 

links. 

The matter of arranging the links and bell-crank movements as 
to overpull or underpull of the links and the bell-crank action depends 
much upon the opinion of designers, in regard to the velocity-stroke 
of the valve, as to which side of the valve may be considered best for 
steam-inlet and exhaust. Four or more bell-crank valve-lever posi¬ 
tions for inlet and exhaust are in use by the leading steam-engine 
builders in the United States. 

Fig. 242 shows the arrangement of the single wrist-plate and its 
link-rod connections, with the valve-levers of the steam side turned 





























































272 


THE CORLISS ENGINE 



downward and those of the exhaust turned upward. The position 
of the wrist-plate and valve-motion is in the middle of their travel. 

In Fig. 243 are shown an elevation and plan of the valve-motion, 
to which is attached Cite’s releasing-valve gear. A is the valve-stem 









































































































































































































THE CORLISS ENGINE 


273 


on a 



and B the valve-lever, and CC' a bell-crank which vibrates loosely 
sleeve around the valve-stem, and is connected by an adjustable link- 
lod to the wrist-plate. The end of the arm C carries a small rock- 
shaft, D, which has a hook, E, fastened on one end. This hook is 
pi ovided with a hardened steel catch-plate, b, which engages a similar 
plate, c, fastened on the end of the valve-lever B, and the hook is kept 
in place by a light spring, /. On the end of the rock-shaft D, opposite 
the hook E, is fixed a forked crank F, hav¬ 
ing a pin on which is mounted a sliding- 
block fitted to move in a slot, i, of a link, 

G. The link is mounted at and vibrates 
about a point, j, in one arm of a bell- 
crank, H, and the bell-crank oscillates 
upon a sleeve around the valve-stem. 

The other arm of the bell-crank H is con¬ 
nected by an adjustable rod, Z, to the 
governor. By an arrangement not shown, 
if the action of the governor become de¬ 
ranged by the breaking of the belt, the 
sudden dropping of the governor-balls 
below their ordinary limit for speed re¬ 
verses the releasing-gear, and the block in 
the slide i is pushed out and prevents the 
hook E from catching the valve-lever. 

In the ordinary regulation for speed the 
block will have been pushed so far out¬ 
ward that it will have slightly turned the 
small rock-shaft D, and moved the hook 
E enough to release the valve-lever B. 

Then the dash-pot will act and close the 
valve. At this moment of release, effected by the toggle-like action 
of the link, the pressure on the bell-crank H, caused by the liberation, 
will be exerted in a radial line from the centre of the slot through the 
point j to the centre of the valve-stem or the stand which supports it, 
and during the entire movement of the hook E there will be no 
appreciable strain to turn the bell-crank H, and consequently there 
will be no strain to disturb the normal action of the governor. As 
the position of the bell-crank H is controlled by the governor, any 




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Fig. 243.—Valve-gear of the 
Fishkill-Corliss engines 











































































274 


THE CORLISS ENGINE 


change in the height of the governor will cause a change in the posi¬ 
tion of the point j, and a corresponding change in the time of release. 

In the following drawings are illustrated the conditions and limita¬ 
tions of the valve-action in the single-eccentric Corliss engine. 



Fig. 244.—Angle of advance. 


Fig. 244 shows the eccentric set at its angle of advance and the 
steam-valves adjusted for the lead, with the crank-pin on the inner 
dead-centre, the closed ports having sufficient lap to insure a steam- 
tight joint. 



The next phase is the point of cut-off, shown in Fig. 245, in which 
the steam-valve of the forward stroke is to suddenly close from a full 
opening at one-third stroke by the release-gear and by the pull of 
the dash-pot with the exhaust-valve at full opening. 



Fig. 246.—Commencement of compression. 


The last phase is the commencement of compression, illustrated 
in Fig. 246, and represented at about one-sixth of the stroke, with the 

































































































THE CORLISS ENGINE 


275 


forward exhaust-valve just closing and the other valves entirely 
closed with their proper laps, due to the required adjustment of steam- 
arid exhaust-valve links. 

In the next three illustrations (Figs. 247-249) the angle of ad¬ 
vance of the eccentric is set at a less angle, say about 100 degrees, 
from the inner dead-centre for one-half cut-off. 



Fig. 247.—Angle of advance. 


In Fig. 247 the eccentric is set at about 10 degrees ahead of 
a right angle from the crank-pin for one-half cut-off, showing the 
steam-valve open by the amount of its lead and the exhaust-valve 
just opening. 



In Fig. 248 the point of cut-off is advanced to one-half the stroke, 
which takes place at the extreme throw of the eccentric, which, with 
the required adjustment of the links, gives a release of the steam-valve 
from full opening and with a full opening to the exhaust-valve. 












































































































276 


THE CORLISS ENGINE 


Fig. 249 shows compression slightly less than in the first set of 
illustrations, Figs. 244-246, and near the extent of the action of a 
single eccentric for the best efficiency in steam-distribution. The ad¬ 
vance of the eccentric may be lessened to 90 degrees from the crank- 
pin, or given a negative place with advance of the cut-off to five- 
eighths, but with restricted port-openings, which can only be given 

their best conditions by double-eccentrics for extended cut-off to 

• 

meet overload. 

For the benefit of students and others interested in the numerous 
designs of releasing-gear for Corliss engines, we give the following 
illustrations and descriptions. 

A standard model of release-gear, illustrated in Fig. 250, is that 
used by the Fishkill Machine Company and others, in which,- A being 
the valve-stem, a bell-crank operated by a connecting-rod from the 



,p 7a7£—' 

Fig. 251.—Bass release-gear. 


Fig. 250.—Bell-crank knock-off. 


wrist-plate lifts the grab-hook E and the valve-arm. An adjustable 
roller at R releases the valve-arm, which is pivoted to the dash-pot 
rod for regulating its fall. The release-roller R is operated by the bell- 
crank H and rod Z from the governor. 

The release-mechanism used on the Bass engines, built by the 
Bass Foundry and Machine Company, is shown in Fig. 251, in which 
the grab-hook consists of a block, C, sliding in a grooved slot in the 
bell-crank lever B, B, and normally forced out to catch the block on 
the rocker-arm at D by a spring. The block C carries a pin, E, on 
the rear side, which is held in contact with a cam-ring, F, having 
two knock-off dies, M and N, on its inside surface. As the bell-crank 
moves in the direction of the arrow from the position shown, the 
roller on the pin E strikes the cam-die. N and is forced rapidly inward, 
releasing the drop-block a. 













THE CORLISS ENGINE 


277 




Fig. 252. — Allis-Chal- 
mers release-gear. 


The release-gear used on the Allis-Chalmers engines is shown in 
Tig. 252. The hook LI, which is forced inward by the spring, engages 
with the valve-lever B, and as the bell-crank lever A, A moves in the 
direction of the arrow, the valve-lever B is lifted 
and opens the valve, and at the proper moment, 
as regulated by the governor, the trip-lever T 
comes in contact with the projection N of the 
cam C, forcing it and the grab-hook outward 
and releasing the drop-lever B, which is brought 
down by the action of the dash-pot. 

In Fig. 253 are shown two positions of the 

release-gear used on the 
engines of the Filer & Sto¬ 
wed Co. 

In this design B is the 

bell-crank, which carries the hook H, mounted 
on a short shaft, and on the other end of 
which is the trip-lever (not 
shown), which engages with 
the knock-off cam C, oper¬ 
ated by the governor-rod. 

K is the drop-lever with 
dash-pot connection. The 
cam-lever C, controlled by 
the governor, limits the 
time of release by the hook 
LI. The lower figure shows 
the position of the parts at the moment of release. 

The valve-gear used on the engines of the 
Nordberg Manufacturing Company is shown in 
two positions in Fig. 254, similar in principle to 
those in Fig. 253, but with an entire change in 
the position of the operating parts. The curved 
bell-crank B carries the grab-hook D, mounted jr IG . 254. — Nordberg 
on a short shaft, and having an arm at the other valve-gear, 

end with a trip-lever, d , which rides on the 
knock-off cam A, the position of which is controlled by the governor 
by pushing the knock-off cam under the grab-hook lever for release. 


lIllTO WRIST PLATE 


Fig. 253.—Trip valve- 
gear. 

































278 


THE CORLISS ENGINE 


The lower figure shows the position of the parts at the moment of 
release. 

The valve-gear on the Sioux City and other engines is shown in 
two positions in Fig. 255. It consists of an inverted or overhead 

wrist-plate connection of the bell-crank lever 
with a forked grab-hook, in which A, A is the 
bell-crank, on one arm of which is pivoted the 
forked grab-hook IT, held by the spring S, the 
other end of the fork riding against the cam C, 
the movement of which by the governor releases 
the valve-arm B. The lower figure shows the 
position of the parts at the moment of release. 

The release-gear of the Scottdale Foundry 
and Machine Company is shown in front and 
side elevations in Fig. 256. The opposite arm 
of the bell-crank A carries the latch-block B, 
which in moving forward engages the block C on 
the valve-arm D, to which is also attached the 
dash-pot rod. The latch-block is pressed down 
by a spring and adjusting thumb-screw at B, 
and is disengaged by the cam E acting upon the 
lever G on a rock-shaft in the valve-arm. A cam at J, also on the 
governor-arm, is a safety-cam, and lifts the lever G and prevents en¬ 
gagement of the latch- 
block, if the governor- 
balls should fall by the 
breaking of its belt. 

A simple and effec¬ 
tive releasing-gear, con¬ 
sisting of few parts, is 
shown in Fig. 257. It 
is used on the engines 
of the Watts-Campbell 
Company. The action of 

this gear is well shown Fig . 256,-Scottdale releasing-gear, 

in the cut, in which A 

represents the crank-arm, which is keyed on the valve-stem and 
carries a steel catch-block a, which is fitted into the end of the crank- 




Fig. 255.—Sioux City 
valve-gear. 
























































THE CORLISS ENGINE 


279 


arm or clrop-lever. B is the bell-crank lever, one arm of which is 
connected with the wrist-plate by the rod b. In the other arm is 
fixed the pin C, which carries the rocker-arm D. A small roller e 
is carried at the upper end of the 
rocker-arm D, and is held against 
the knock-off cam E by the spring c, 
as shown. 

When the bell-crank moves in 
the direction of the arrow, the edge 
of the die-block / engages the end of 
the valve-arm A, and raises it to the 
point of release. At this point the 
roller e at the upper end of the 
rocker-arm D comes in contact with 
the projection of the knock-off cam, 
which forces the roller and upper 
end of the rocker-arm outward, releasing the arm A, which is rapidly 
drawn downward b}^ the dash-pot and the rod F. 

There are many other models of releasing-gear in use, all of which 
involve the foregoing principles; but enough have been illustrated 
for the understanding of their principles of action to meet the ordinary 
wants of engineers in engineering possibilities, such understanding 
fulfilling our principal aim. 



Fig. 257.—Watts-Campbell releasing- 
gear. 


GOVERNORS AND DASH-POTS 

The types of governor best suited for the speed-regulation of 
engines of the Corliss type appear to be those of the fly-ball and 
gravity-weight combination, although other models are in use which 

seem to give satisfactory control. 

In Fig. 258 is shown the leading model of the class of the fly-ball 
gravity-governors, the Porter-Allen, as made by the Southwaik 
Foundry and Machine Company. It consists of a pear-shaped weight, 
A, moving freely on the spindle, the balls B, B being attached to the 
spindle cross-bar and to the cross-bar of the weight by rods with forked 
toggle-joints. A lever, D, pivoted to an arm on the governor-frame 
and traversed by a pin-connection with a ring in the grooved sleeve 



















280 


THE CORLISS ENGINE 


at the bottom of the gravity-weight, is connected to the valve-gear at 
E and adjusted by a counterweight at C. 

A modification of this governor as made by the Watertown Engine 
Company is shown in Fig. 259, in which a much larger movement 
of the lever F and knock-off cam-rods E, E is obtained. The upper 
yoke, to which the arms of the governor-balls are pivoted, is fitted 
loosely to the spindle, the latter carrying a rack with which mesh 
the extensions of the arms to which the balls are attached, these being 
in the form of a sector of a gear. When the balls fly outward the ful- 




Fig. 258. Porter-Alien governor. Fig. 259. — Watertown governor. 


crum of the arms carrying the balls is raised a certain distance, which 
increases the height of the central weight over that due to the eleva¬ 
tion of the balls, so that a slight change in the position of the balls 
will cause the weight, and consequently the knock-off cams, to move 
a much greater distance than that due to the movement of the balls 
only. The twofold action thus obtained makes an exceptionally 
sensitive governor, without excessive travel, and without a jerk or a 
tendency to fluctuate. 

The governor used on the Lane & Bodley engine differs materially 
in its generating action from the models last described and is illustrated 
in Fig. 260. The governor-balls are fixed at the ends of bell-crank 
levers which are supported by a circular plate. The horizontal arms 


































































THE CORLISS ENGINE 


281 


of the bell-crank levers are provided with rollers for the purpose of re¬ 
ducing the friction between them and the collar and sleeve which 
surround the spindle. 

The outward and downward movement of the balls is resisted by 
the spring which opposes the upward movement of the sleeve. At 
the lower end of the sleeve is a groove in which is fitted a collar carrying 
one end of the bell-crank lever, to which is attached the rod operating 
the knock-off cams, the cam-connections being over and under with 
a continuous rod. It will be noticed that a very slight vertical move¬ 
ment of the collar will move the lower end of the lever and the governor- 
rods a considerable distance. The speed of this governor is about 
200 revolutions per minute, which renders it capable of producing a 
great change of centrifugal force for 
a slight variation in speed and with a 
corresponding insensibility to vary¬ 
ing internal resistances. While the 
changes in position are made very 
quickly, there is no jerk or vibration, 
for the dash-pot at the base of the 
governor-post prevents a very sud¬ 
den upward or downward movement 
of the spindle. The action of the 
automatic stop S may be readiy un¬ 
derstood, and is shown in its work¬ 
ing position. Fig. 260.—Lane & Bodley governor. 

When the engine is to be started, 

the handle on the stop is raised, which raises the governor-sleeve by 
means of a cam, and moves the knock-off cams on the valve-stems 
enough to allow the hook to engage with the catch-hook. 

As soon as the governor comes up to speed, the governor-sleeve 
rises, which allows the weight of the stop-handle to turn the cam and 
bring the lower face under the sleeve, so that, should the gOA^ei noi stop, 
the sleeve will descend low enough to allow the knock-off cam to 
prevent the hook from engaging with the catch-block, thus insuiing 

against the opening of the valves. 

In Fig. 261 is represented the slow-speed governor used on the 
Scottdale Corliss engine. Its lifting-power is augmented by the 
lever-connections on long arms and light balls, which, at a low \ eloeity, 








































282 


THE CORLISS ENGINE 


about 60 revolutions per minute, give sufficient lifting-power to oper¬ 
ate the gravity-weight. The bell-crank is connected to the sliding- 
sleeve by a short rod, and upon the other end of its shaft are fixed a 
lever and its adjusting weight. A retarding annular dash-pot around 
the spindle regulates the action of the balls and also catches the oil 
dripping from the collars. The governor is also provided with an 

automatic safety-stop, supported, when not 
in action, by the governor-belt, and requir¬ 
ing no attention when the engine is started 
or stopped. 

Of the great variety of pulley- or fly¬ 
wheel governors there seem to be two classes 
as regards manner of movement of the ec¬ 
centric, one of which consists in shifting 
the eccentric and the other in rotating the 
eccentric on a fixed centre. The mech¬ 
anism for obtaining these movements is 
mostly of the centrifugal order, but in¬ 
ertia and positive mechanical devices are 
also in use. 

Of the shifting eccentrics, we illustrate 
in Fig. 262 the simple device used on the 
Sweet straight-line engine. In this gover¬ 
nor the slotted eccentric has two opposite 
arms, one end of which is pivoted to an 
arm of the pulley or fly-wheel, and the 
other to a link, moved by a lever and by 
the centrifugal action of a weight, and 
restrained by a leaf-spring. 

In Fig. 263 is shown another design of 
shifting eccentric. In this the two weights 
are connected for equal movement by a link, and each balanced by a 
helical spring. The eccentric-arm is pivoted to an arm of the pulley 
or fly-wheel and also to the end of one of the weights, so that excess 
of speed throws the eccentric toward its centre of rotation. 

In Fig. 264 is shown the pulley-governor used on the engines of 
the Fitchburg Steam Engine Company. It will be seen that when the 
weights c, c, respectively, are moved outward by centrifugal force, 



Fig. 261.—Scottdale governor. 






































































THE CORLISS ENGINE 


283 


they draw the eccentric across the shaft by means of the links d, d. 
The weights e, e are for the purpose of counterbalancing the weight of 
the eccentric-strap and one-half the weight of the eccentric-rod in hori¬ 
zontal engines, and the total weight of these members in vertical 


Fig. 262.—Sweet's governor. Fig. 263.—Shifting eccentric-governor. 

engines, which leaves no work upon the governor-weights but to shift 
the eccentric when the load upon the engine changes. The springs 
oppose the outward movement of the governor-weights c, c, by means 
of which the speed of the engine may be changed. 

It will be apparent that by tightening the springs the speed of 
the engine may be increased, and by loosening them the opposite 
result will be obtained. The maximum range of cut-off is from zero 
to three-fourths stroke, which enables the engine to maintain a uniform 
speed under wide variations of load. 

Of the rotating eccentric-governors there are a number of designs, 

a few of which we select to show the 
main points of variation. 

In Fig. 265 is shown the pulley- 
governor used on the Buckeye engine, 


Fig. 264.—Fitchburg pulley-governor. Fig. 265.—Rotating eccentric-governor. 






in which the centrifugal force of two pivoted weights connected to a 
spiral-slotted face-plate by the links 1), D oscillates the face-plate. 
An arm, E, on the eccentric carries an adjustable wrist-pin by which 





























284 


THE CORLISS ENGINE 


the eccentric is rotated, and on an extension of the arm on the other 
side of the eccentric is a wrist-pin which allows of a reversion of the 

eccentric. 

In Fig. 266 is shown 
the governor of the Mc¬ 
Intosh & Seymour Co. on 
their multiported four 
slide-valve engines. In 
this governor the cut-off 
eccentric is free to re¬ 
volve on the shaft, and is' 
connected to the weights 
c, c by the links d, d. 
The outward movement 
of the weights is resisted 
by the leaf-springs e , e, 
while any tendency to 
sudden fluctuations in 
Fig. 266.—Dash-pot governor. th^ position of the 

weights is prevented by 
the dash-pots /, /. The ends of the springs are connected to the 
weights by means of telescopic pins, g, g ; lengthening these pins in- • 
creases the compressive effect of the spring, and thus offers greater 
resistance to the weights. To increase the 
sensitiveness of the governor, therefore, 
these pins must be lengthened, and if the 
governor is too sensitive they must be 
shortened. The circular openings in the 
weights are provided with extra weights in 
the form of bushings. The speed of the 
engine is changed by changing these bush¬ 
ings, inserting heavier ones when the speed 

is to be reduced and lighter ones when it is p IG> 267. _Inertia-governor. 

to be increased. 

In Fig. 267 is shown an inertia-governor, in some designs of which 
the momentum of the weights and the centrifugal force are combined 
factors in the operation of varying the position of the eccentric, either 
by rotation or by shifting it from its centre. The illustration shows 
































THE CORLISS ENGINE 


285 


the inertia-governor used on the Leffel engine. The weights B, IT are 
balanced, with their centre of gravity at the centre of the engine-shaft, 
but pivoted at A to the fly-wheel, and by an arm to the eccentric at p. 
The spring K holds the weights to their normal position, their range 
of motion by differential momentum from variable speed of the engine 
being limited by the stops on the rim of the fly-wheel or pulley. 


THE VACUUM DASH-POT 

The dash-pot is one of the most essential adjuncts of the Corliss 
type of engine. The speed and softness of the valve-closure are due 
to the perfect action of the dash-pot, and as there are several designs 
in use we illustrate some of their features and manner of action. 

In Fig. 268 is shown a section of the dash-pot used on the Frick 
engine. It is a dust less dash-pot, as the air that is drawn under the 
piston in its upstroke is exhausted into the same annular chamber 
from which it is taken, which also renders the 
dash-pot noiseless in operation. As the plunger 
P is drawn upward by the valve-gear, air is 
drawn into the plunger-cylinder from the annular 
chamber A, through the check-valve c. The air 
is not sufficient, however, to prevent the for¬ 
mation of a partial vacuum, which draws the 
plunger quickly downward when the valve- 
spindle is released. As the plunger nears the 
bottom of the cylinder it is cushioned by the air, 
which is forced back into the outer chamber 
through the poppet-valve V. The degree of cushioning can be accu¬ 
rately adjusted by means of the screw S. 

In Fig. 269 is shown in section and elevation the dash-pot used 
on the Watts-Campbell engines. This dash-pot is very simple, and 
consists of a cup-cylinder having a tapered lower portion which sur¬ 
rounds the plunger, as shown. The plunger is made to fit over the 
central column in the cylinder, so that when the plunger is drawn 
upward a partial vacuum is formed in the space between the plunger 
and the column. The annular space around the piston-end ol the 
plunger allows a free fall of the plunger by the vacuum effect until 



pot. 


































286 


THE CORLISS ENGINE 


it reaches the taper closure near the bottom of the cup-cylinder. 
The cushioning effect is produced by the escape of the air from the 
annular space at the bottom of the cylinder, which continues until 
the plunger^reaches the straight portion of the bore. 



Fig. 269.—Cup-cylinder dash-pot. 


The remainder of the air thus entrapped is expelled through the 
small valve, which offers greater or less obstruction to the small exhaust- 
port shown at the bottom. A spring check-valve in the head of the 
central column is an air-relief, and the small screw at the top regulates 
the vacuum. 

SETTING THE VALVES AND GEAR OF A 

CORLISS ENGINE 

Every engineer on taking charge of a Corliss type of engine should 
have at hand a detailed description of its special action and govern¬ 
ment, with directions of the builders for setting and adjusting the 
valves and valve-gear. The variety of motions and kinks in regard 
to the setting and proper adjustment of valves and gear, including 
rods, links, eccentric, governor, and dash-pots, differs so much in 
details of design—although the general principles of operation are 
essentially alike—that only a general description and illustration for 
setting the valves and valve-gear can be attempted here. It is 
hoped that they may be useful as an aid to the new engineer when 
special instructions are not at hand. 

With the first examination of the engine to find if every part of 












































THE CORLISS ENGINE 


287 


its running-gear is in working order, see that the builders’ marks on 
the valves and cylinder, as also those on the wrist-plate hub, are in 
alignment when the wrist-plate is on its central position and the centre 
line of the rocker-arm is in a vertical position, as shown in Fig. 270, 
with the eccentric at right angles to the central line of the engine and 
the crank-pin following the right angle plus the lead. The reach-rod 
and eccentric-rod being both adjustable, any variation from the proper 
position may be readily made. 

In this position, on removal of the back bonnets the builders’ 
marks on the end of the valve and cylinder will indicate the opening 



Fig. 270 —Central position of the wrist-plate and rocker-arm. 


edge of the valve and port and the lap. On the shoulders of the 
wrist-plate and its pin find, or make, a mark like b a in E ig. 271, which 
should coincide with the central position of the wrist-plate. 

Set the wrist-plate in its central position by an extra washer 
under the nut of the wrist-plate pin, and then adjust the valves lor 
their proper positions by regulating the link-length foi each valve. 
Then by turning the wrist-plate to its extreme positions, as shown in 
Fig. 272, connect the dash-pots so that when down the hook will catch 

with sufficient room to insure locking. 

The governor should be blocked up to about the running position, 
to allow of the free action of the release at this position of the governor- 

cam. 

The wrist-plate should be turned from one extreme position to 














288 


THE CORLISS ENGINE 


the other, so as to open the valves alternately and allow the dash-pot 
plungers to seat properly, and in order so that the hooks may engage 
the catch-blocks without fail when the wrist-plate is rocked to its ex¬ 
treme positions. Hook the reach-rod onto the wrist-plate with the 
eccentric nearly in its extreme position, and adjust its length so that the 
lines on the wrist-plate hub will nearly coincide. Adjust the length 
of the governor-rod corresponding to the valve—which is now open— 
so that the inner member of the hook just engages the projection 
on the knock-off cam. Move the wrist-plate, by turning the eccentric, 



Fig. 271.—Wrist-plate in its cen- Fig. 272.—Extreme positions of the wrist-plate, 

tral position on the centre. 


until the lines on the hub coincide. The valve, which has been raised, 
should now be released and the dash-pot plunger properly seated. 
The governor-rod should be so adjusted that the steam-valve may 
be released by the time the wrist-plate reaches the extreme position, 
in order to insure the valve being closed when the latest point of cut-off 
is reached, which point corresponds to the extreme position of the wrist- 
plate and eccentric, and to the governor in its lowest operative 
position, viz., with the collar or sleeve resting on the safety-stop. 
The governor-rod at the opposite end of the cylinder should be similarly 
adjusted. 

As the valve-ports open on the inside or outside in different engines, 
the positions of the builders 1 marks on the valves must be considered 
by a reversal of the positions of their connections. 

Having made the adjustment of the steam-valves, treat the 
exhaust-valves in the same way, with the exception of the amount of 
lap, which should be negative. 

The following table shows the usual practice for lap, lead, and 
exhaust-release for various sizes of Corliss engines, which may be 
variable to suit the methods of different designers: 







































THE CORLISS ENGINE 


289 


Table XXXIV.—Lap, Lead, and Exhaust-Release. 


Size of engine. 

Revolutions per minute. 

Steam-lap, 

inch. 

Steam-lead, 
inch. 

Exhaust- 
release, inch. 

12X36-48 

90-85 

1 6 

1 6 

1 

'3 2 

14X36-48 

85-75 

L 

4 

i 

3T 

1 

3 2 

16X32-48 

85-75 

A 

1 

3 1 

-i- 
3 2 

18X36-48 

80-75 

3. 

8 

l 

64 

l 

16 

20X42-60 

75-65 

2. 

8 

1 

"6 4 

i 

1 6 

22X42-60 

75-65 

A 

JL. 

64 

A 

24X42-60 

75-65 

A 

1 

6 4' 

A 

26X48-60 

70-65 

A 

FT 

A 

28X48-72 

65-55 

A 

FT 

A 

30X48-72 

65-55 

15. 

3 2 

FT 

i 

32X48-72 

65-55 

I 

FT 

1 

8 

34X48-72 

65-55 

2 

JL 

FT 

i 

36X48-72 

62-55 

a 

1 

FT 

1 

38X60-72 

60-55 

It 

3 i 

A 

A 

40X48-84 

60-55 

£L 

YF 

A 

3. 

1 6 

42X48-72 

70-55 

9 

TIT 

A 

A 


In Fig. 273 is shown a sketch of a Corliss engine of the Hamilton 
design, with single wrist-plate and trip valve-gear, governor, and dash- 
pots. The lap-movement of the steam-valves is outside or toward 
the ends of the cylinder. The exhaust-valves open on the inside 



Fig. 273.—Hamilton Corliss engine. 


or toward the centre of the cylinder. A stop-motion is carried by 
the governor for preventing a runaway in case the governor-belt 
should break. 

A tandem compound Corliss engine of the Atlas type is sketched 
in Fig. 274. The steam-valve gear of this engine for both high- and 











































290 


THE CORLISS ENGINE 


low-pressure cylinders lias a through line of connecting-rods from 
one eccentric and a through line of connecting-rods from the other 
eccentric to the valve-arms on each cylinder. The governor controls 



Fig. 274.—Tandem Corliss engine. 


the steam- valves of the high-pressure cylinder, which open on the inside 
or toward the centre of the cylinder. 

In Fig. 275 is shown a sketch of the cylinder and valve-gear of the 
Corliss engine of the C. & G. Cooper design, with two wrist-plates and 



Fig. 275.— Cooper Corliss engine. 


two eccentrics whose rods are transmitted to the valve-gear through 
two rocker-arms. 

The question of a right- and left-handed engine is often raised, and 














































































































THE CORLISS ENGINE 


291 


occasionally lias been the subject of serious discussion. In Fig. 2/6 
we give a sketch from good authority as to the positions of a right- and 


o 

c 

r+ 

DO 

o 

p 


D3 

CD 

P 

3 * 

OP 

“n 

o 

c 

3 

Q_ 

P 

r+ 

o* 

3 



o 

c 

r-+- 

oo 

o 

p 


03 

(D 

p 

35 < 

3’ 

OP 

■n 

o 

c 

3 

Q. 

P 

r-4- 

o* 

3 


Fig. 276-Left-handed and right-handed engines. 


a left-hand engine. When standing at the cylinder and looking toward 
the shaft, a right-hand engine has the valve-gear on the right-hand 
side, and vice versa. 













































































































































































































CHAPTER XVII 


COMPOUND ENGINES 

The simple compounding of the steam-engine is a source of econ¬ 
omy over the single-cylinder non-condensing type wherever water for 
condensation cannot be made. available. The simple condensing- 
engine was formerly the most important step in the progress of steam- 
power, until followed by the multicylinder compound condensing type, 
of which simple compounding is probably the most economical method 
of developing power from high-pressure steam where condensing water 
is not available. This system is now being largely adopted for loco¬ 
motive service and for localized power as a means of greater expansion 
from higher pressure and with high speed. The loss by cylinder- 
condensation is lessened by compounding, as is approximately shown 
in the following table: 


Table XXXV.—Percentage of Loss by Cylinder-Condensation. 


Percentage of stroke 
completed at cut-off. 

Simple engines. 

Compound engines, 
high-pressure cylinder. 

Triple-expansion en¬ 
gines, high-pressure 
cylinder. 

5 

42 ’ 



10 

34 

26 


15 

29 

24 

22 

20 

26 

22 

20 

30 

22 ' 

18 

16 

40 

18 

15 

13 

50 

14 

12 

10 


The water-consumption in a compound engine as compared with 
a single-cylinder non-condensing engine is shown approximately in 
the following table, general conditions only being considered: 

The value in compounding the expansion of steam for power 
has been amply shown in a practical way by the experience of the 
past two decades, in which its multiple effect reached its fourth stage; 
further advance in this line seems impracticable from the near safety- 
limit of boiler-pressures to the tensile strength of material for practical 
and economic construction. 

292 











COMPOUND ENGINES 


203 


Table 


XXXVI. —Water-Consumption in Compound 

Engines. 


and 


Single-Cylinder 


Cut-off, 
per cent. 

Initial pressure by gauge. 

Mean effective pressure 
gauge. 

Feed-water 
per indicated 
horse-power 
per hour, 
pounds. 
Compound 
engine. 

Feed-water per 
indicated 
horse-power 
per hour, 
pounds. 
Single cylinder. 

High-pressure 

cylinder, 

pounds. 

Low-pressure 

cylinder 

pounds. 

High-pressure 

cylinder, 

pounds. 

Low-pressure 

cylinder, 

pounds 

absolute. 


80 

4.0 

11.67 

2.65 

16.92 

29.88 

10 ] 

100 

7.3 

15.33 

3.87 

15.00 

25.73 


120 

11.0 

18.54 

5.23 

13.86 

21.60 

( 

80 

4.3 

26.73 

5.48 

14.60 

25.68 

20 \ 

100 

8.1 

33.13 

7.56 

13.67 

23.77 

l 

120 

12.1 

39.29 

9.74 

13.09 

21.86 

( 

80 

4.6 

37.61 

7.48 

14.99 

26.29 

30 ] 

100 

8.5 

46.41 

10.10 

14.21 

24.68 

l 

120 

11.7 

56.00 

12.26 

13.87 

23.07 


The liability to self-destruction in both boiler and engine is very 
great, as is also their cost at the highest pressure now in use—say, 
200 pounds per square inch. 

The experiments of Perkins in England many years since with 
steam at 250 pounds pressure for power purposes, ended in practical 
failure, and was followed by Reed and others in the United States 
with like results. Steam at 1,000 pounds pressure was used by Per¬ 
kins, and was repeated by the author in New York with a Perkins 
gun, with practical failure as to its merit; and all these lessons are 
probably lost to the present ambition of the engineering world. 

Below a limited high pressure the economy of compounding or 
multiple expansion is found in a reduction in the size of parts—making 
a lighter and less costly engine for a given power; giving in a two- or 
three-crank engine a more uniform twisting or turning moment, with 
smaller strains in the engine; enabling a smaller fly-wheel and its strain¬ 
ing moments, and resulting in a more uniform motion where a fly-wheel 
is not used—and in making the range of temperature less in each 
cylinder, and thereby lessening the total loss in steam per indicated 
horse-power. 

The highest efficiency of the compound non-condensing engine 
requires a proportion of cylinder-volumes, initial pressure, and cut-off 
that will give the terminal pressure in the low pressure at from 2 to 3 
pounds above the atmosphere. 






















294 


COMPOUND ENGINES 


The compound non-condensing engine has two phases in its action, 
one of which is a direct discharge from the high-pressure cylinder to 
the low-pressure cylinder, as in the Woolf type; the other has a receiver 
between the cylinders. Of the first, the Westinghouse, Buckeye, and 
Ball engines are examples; but these may be made condensing by a 
small change in cylinder-volumes. 

The relative areas of the high- and low-pressure cylinders for 
non-condensing and condensing compound engines of the Buckeye 
Engine Company are here given for various pressures in their tandem 
type. 


Table XXXVII.— Cylinder Proportions for Non-Condensing and Condensing 

Compound Engines —Two Cylinders. 


• Steam. 

Non-Condensing Com¬ 
pound Engines. 

Condensing Compound Engines. 

150 pounds. 

125 pounds. 

150 pounds. 

125 pounds. 

100 pounds. 

Small engines. 

Large engines. 

. 

1 to 3.71 

1 to 3.64 

1 to 3.20 

1 to 3.06 

1 to 4.30 

1 to 4.00 

1 to 3.71 

1 to 3.64 

1 to 3.10 

1 to 3.06 


An example of the tandem compound high-speed engine is illus¬ 
trated in Fig. 277, and represents a vertical section of the Harrisburg 
four-valve type with Corliss valves. The steam-valves are controlled 



Fig. 277.—Harrisburg tandem compound engine. 


by a fly-wheel governor and movable eccentric, while the exhaust- 
valves receive their motion from a fixed eccentric, which admits of a 
variable cut-off and positive exhaust-opening. 





























































































































COMPOUND ENGINES 


295 


In Fig. 2/8 is shown a section of the cylinders and piston-valve 
of the Vauclain compound engine for locomotive service. A high- 
pressure and a low-pressure cylinder in a single casting are used on 
each side of the locomotive; the pistons are connected to a common 
cross-head, while a single piston-valve controls the events for both 
cylinders. 

The action of the steam in this system is as follows: Steam is 
admitted outside of the piston-valve A, and, when the valve is moved 
to the right, enters the left end 
of the high-pressure cylinder. 

This action allows steam to 
exhaust from the right-hand 
end of the high-pressure cylin¬ 
der through the hollow space B, 
in the centre of the valve A, to 
the left-hand side of the low- 
pressure piston, while steam on 
the right escapes through the 
exhaust-cavities C, C around 
the valve. At the proper time 
steam is cut off from the high- 
pressure cylinder and expan¬ 
sion takes place. This is fol¬ 
lowed by the closing of the 
exhaust on the other end of the 
high-pressure cylinder, which cuts off the steam in the left end of the 
low-pressure cylinder, and hence expansion occurs here also, while 
compression takes place in the right-hand end of the high-pressure 
cylinder. A starting-valve is used, connecting to both ends of the 
high-pressure cylinder, and opening to the low-pressure cylinder for 
starting. 

A later design of the Vauclain type is a balanced engine in which 
the motions of the high- and low-pressure pistons and connections 
are in opposite directions, as shown in Fig. 279. The cylinders are a 
development of the original Vauclain four-cylinder compound type, 
with one piston slide-valve common to each pair. Instead of being 
superimposed and located outside of the locomotive-frames, the cylin¬ 
ders are placed horizontally in line with one another, the low-pressure 

























































































































296 


COMPOUND ENGINES 


outside and the high-pressure inside the frames. The slide-valves 
are of the piston type, placed above and between the two cylinders 
which they are arranged to control. A separate set of guides and 
connections is required for each cylinder. The two high-pressure 
cylinders being placed inside the frames, the pistons are necessarily 


Starting Valve 


coupled to a crank-axle. The low-pressure pistons are coupled 

to crank-pins on the outside 
of the driving-wheels. The 
cranks on the axle are set at 
90 degrees with each other, 
and at 180 degrees w r ith the 
corresponding crank-pins in 
the wheels. The pistons, 
therefore, travel in the oppo¬ 
site direction; and the recipro¬ 
cating parts act against and 
balance one another to the 
extent of their corresponding 
weight. 

The distribution of steam 
is shown in the diagram (Fig. 
279). The live-steam port in 
this design is centrally located 
between the induction ports 
of the high-pressure cylin¬ 
der. Steam enters the high- 
pressure cylinder through the 
steam-port and the central ex¬ 
ternal cavity in the valve. The exhaust from the high-pressure cylinder 
takes place through the opposite steam-port to the interior of the valve, 
which acts as a receiver. The outer edges of the valves control the 
admission of steam to the low-pressure cylinder. The steam passes 
from the front of the high-pressure cylinder, through the valve, to 
the front of the low-pressure cylinder, or from the back of the high- 
pressure to the back of the low-pressure cylinder. The exhaust from 
the low-pressure cylinder takes place through the external cavities 
under the front and back portions of the valve, which communicates 
with the final exhaust-port. The starting-valve connects the two 



Fig. 279.—Balanced compound cylinder. 
Vauclain. 




























































































































































COMPOUND ENGINES 297 

live-steam ports of the high-pressure cylinder, to allow the steam to 
pass over the piston. 

In Fig. 280 are shown a vertical section and a cross-section of a 
convertible compound engine, the Flinn type for steam-automobiles 
and -trucks. Steam enters at the centre of the high-pressure steam- 
valve, and when the intercepting valve is in the position shown in the 
left cross-section, it can pass from the high-pressure chest directly 
to the low-pressure chest, allowing both cylinders to run with high- 
pressure steam, the high-pressure exhausting at A into the main 
exhaust-chest. This gives great starting or climbing power to the 
vehicle. Otherwise the intercepting valve is turned to the position 
shown in the right-hand lower section, closing the free exhaust from 
the high-pressure cylinder and the live-pressure connection to the low- 
pressure steam-chest (compelling the exhaust of the high-pressure cylin¬ 
der to enter the receiver) and to the low-pressure valve. 



Fig. 280.—Convertible compound engine. 


A non-condensing compound engine with contiguous cylinders 
and pistons connected to a common cross-head is shown in Figs. 281 
and 282—the product of the American Engine Company. It is a high¬ 
speed engine in which simplicity and compactness have been realized 
to a high degree. The valves are of the duplex-piston type on a 
single rod, and are operated from an outside crank-pin and centrifugal 
governor on the outside of the fly-wheel, which method makes an 
automatic adjustment simultaneously for both valves. 







































































































































298 


COMPOUND ENGINES 


The arrangement of pistons and cross-head will be understood by 
reference to Fig. 282. The cross-head here shown is designed with 
a view to securing the greatest strength and rigidity with the least 


Fig. 281.—Elevation—duplex compound engine. 



weight. The length is made equal to about twice the length of stroke 
of the engine, so that its smoothness of running is quite independent 
of any unequal division of work between the pistons, if such should 
occur; but because of the simultaneous cut-offs in both cylinders the 



Fig. 282.—Vertical section—duplex compound engine. 


work is divided almost exactly between the two pistons at all stages 
of load, from the simple friction load to the fullest overload capacity. 
A feature of this construction which appeals to the engineer in 


















































































































































































































































COMPOUND ENGINES 299 

comparing it with the tandem compound is the fact that both pistons 
are as accessible as with the simple engine. 

The indicator-diagrams (Fig. 283), taken from a nominally 80 
horse-power engine with cylinders 9jx 15x11, at 275 revolutions, 
100 pounds pressure, show remarkable uniformity in the division of 
work at greatly varying loads, which was 38 horse-power for the upper 
card and 85 horse-power for the lower 
card. Practically the same proportions 
are shown by the cards of the larger 
condensing-engine of the same type. 

A. single-acting vertical cross-com¬ 
pound engine with cranks at 180 degrees 
and in which a single piston-valve set 
crosswise on the heads of the contiguous 
cylinders controls the steam-distribu¬ 
tion, is shown in the longitudinal. and 
cross sections, Fig. 284. It is a novel 
and very compact high-speed motor for 
all purposes, and is especially suited for 
direct connection to electric generators. 

The steam-chest is a separate casting 
bolted to the cylinder-heads, and con¬ 
tains the steam-passages and the trans¬ 
fer-passage from the high- to the low- 
pressure cylinder. The pistons are of 
the trunk type, the low-pressure cylinder 
having an inserted trunk-bearing sleeve 
that encloses cushion-spaces, Y, Y of air- 
or steam-leakage, which is drained by 
the pipe and valve at g. The sleeve in Fig. 283. — Indicator-diagrams, 
the low-pressure trunk being of equal 

area with the high-pressure trunk, it serves to prevent unequal pressure 
in the base A and discharge at the overflow W and at the air- or 
steam-vent Z. The spool piston-valve H travels in a multiported 
liner which gives ample port-opening for high speed. The steam- 
chest P and the exhaust-chest T completely surround the liner. . The 
passage X is a by-pass to the neck of the spool-valve for admitting 
steam to the low-pressure cylinder in starting, the liner having a set 




































300 Fig. 284. —Westinghouse cross-compound single-acting engine. Longitudinal and cross sections. 

















































































































































































































































































































































COMPOUND ENGINES 301 

of ports to meet this purpose; d is a relief-valve for each cylinder. 
The centrifugal governor is enclosed in the fly-wheel at F. 

In Fig. 285 is a combined diagram of the distribution of steam- 
pressure in the Westinghouse vertical compound engine, taken on the 
same card at 90 pounds boiler-pressure. The same would be obtained 
if thev were taken with different indicators, but with the same num- 
ber of spring. The cut-off point is c in the high-pressure cylinder, and 
exhaust begins at e, but as there is only the small steam-chest of the 
low-pressure cylinder to exhaust into, the line eh is not steep. At h 
the low-pressure valve opens the port to that cylinder, and we get the 
steam rapidly exhausting from the high pressure to the low. This is 



Fig. 285.—Diagram from the Westinghouse single-acting compound engine. 

shown by the drop below h and the rise above i. The two pencils 
arrive at h and i simultaneously. The vertical line above i would 
meet that below h but for the resistance offered by the ports to the 
passage of steam from one cylinder to the other. From h to b steam 
is continually passing out of the high-pressure cylinder into the low, 
the corresponding points in the latter diagram being i and d. The 
cause of the fall toward d is due to the space occupied by the steam 
in the low-pressure cylinder, combined with that in the high-pressure 
cylinder together growing larger, and consequently the pressure must 
grow less. At b the exhaust-port in the high-pressure cylinder closes, 
and compression begins. Further, as no more steam is coming from 
the high-pressure cylinder, the steam in the low begins a slightly 
different expansion-line, dn, until at n exhaust begins. Compression 
begins at a and ends at i, where admission commences. 

In Fig. 286 is given a diagram of a test made to determine the 





302 


COMPOUND ENGINES 


steam-consumption and the mechanical efficiency and regulation of a 
Buffalo 12 and 18 X 10-inch horizontal, tandem-compound, high-speed, 
non-condensing engine; steam-pressure, 125 pounds. In this engine 
the high-pressure valve takes steam on the inside, and exhausts around 
the ends. The steam then passes through the cast port in the bottom 
of the high-pressure cylinder to a receiver-pipe on the opposite side, 
and then to the low-pressure valve-chest. The steam is led to an 



Horsepower 


Fig. 286.—Diagram of steam-consumption and efficiency. 

exhaust-outlet at the bottom of the low-pressure valve-chest. The 
high-pressure valve is a piston, while the low-pressure valve is a slide, 
with a balance-plate on the back. The two valves are moved by 
independent eccentrics and rods, the two eccentrics being on opposite 
sides of the engine. 

Governing is obtained entirely at the high-pressure valve, the 
motion of this valve being controlled by a centrifugal or shaft governor. 
The engine was set to run at about 285 revolutions. 

The diagram shows curves of the steam-consumption for non¬ 
condensing tests and the mechanical efficiency. Steam-consumption 
is figured for dry steam, the steam being at no time over 4 per cent, 
moisture in the main and usually less than 3 per cent. Curve A 
shows the relation between developed horse-power and steam per 
developed horse-power hour, curve B between indicated horse-power 
and steam per indicated horse-power hour, and curve C between de¬ 
veloped horse-power and mechanical efficiency. 




























































































































































































































































































COMPOUND ENGINES 


303 


In Fig. 287 is given a diagram showing the efficiency and steam- 
consumption in a test of a Reeves vertical cross-compound non-con¬ 
densing engine, 12 and 20 X 14 inches, and a condensing-engine 
10J and 20 X 14; it shows the difference in efficiency and steam- 
consumption under like conditions of steam-pressure and valve-gear. 
The ratio of cylinder-volume for the condensing trial was 1 to 3.6, 
vacuum 24-inch, and for the non-condensing trial 1 to 2.75, and nor¬ 
mally 160 horse-power. 

In this test the power was measured by the use of a Prony brake, 
and the steam-consumption and efficiency, over a considerable range 



20 ' 40 60 80 100 120 140 160 180 200 

Horsepower 


Fig. 287.—Comparative diagram of efficiency and steam-consumption in 
non-condensing and condensing engines. 


of load, are easily seen from the curves. Two things may be noticed, 
however: The cut-off, even at the higher loads, does not seem to be 
late enough to cause any marked rise in the steam-consumption; and 
the mechanical-efficiency curves show a steady increase with the load 
at any given steam-pressure, and the efficiency falls off but slightly 
on overload. 






















































304 


COMPOUND ENGINES 


II E C E I V E R S 

A receiver is not essential to a compound tandem engine with 
immediate connections between the cylinders, although the usual 
pipe-connections operate in a small measure as a receiver. With 
cross-compound engines with cranks at 90 degrees, the receiver 
modifies the steam-expansion to a considerable extent. 

The distribution of the steam in the cylinders ot a tandem com¬ 
pound engine, at various points of the stroke, is graphically shown 
in the diagram (Fig. 288), neglecting clearance- and steam-passages. 
In the diagram ab = volume of the high-pressure cylinder; ac = volume 
of low-pressure cylinder = 1 to 4; the vertical line ad = initial pressure; 
exhaust of high pressure is at f, one-third cut-off; initial pressure of 
low-pressure cylinder = ag = terminal pressure of the high-pressure 
cylinder and takes steam to the end of the stroke; the curve gmk 
represents the fall of pressure in the low-pressure cylinder, and the 
curve fnh represents the decreasing back pressure in the high-pressure 


d e 



Fig. 288.—Diagram, without receiver, of tandem compound engine. 

cylinder (each shaded section representing the theoretical indicator- 
diagram for its steam-pressure); pn = rm, and ck = ah. 

In Fig. 289 is a diagram of the distribution of steam as well 
as the theoretical indicator-card for each cylinder, representing the 
shaded part. Volume of cylinders, 1 to 3; cut-off, one-half in each 
cylinder. Then, if the steam be admitted to the high-pressure cylinder 
for one-half the stroke, de = \ ab is the line of admission, e is the point 
of cut-off, and ef the curve of expansion to the end of the stroke of the 







COMPOUND ENGINES 


305 


high-pressure cylinder, the terminal pressure being bf = J ad. Com¬ 
munication is now opened with the receiver, and the pressure falls to 
g, the pressure bg depending on the volume of the receiver and on the 
pressure ot the steam in it. But there is as yet no admission to the 
low-pressure cylinder till another half-stroke has been made. The 
diagram ot work done by the high-pressure piston will therefore show 
an increasing back-pressure curve, gt, as that piston returns, till it 


d e 



reaches half-stroke, when the low-pressure steam-port opens and 
admits steam at the initial pressure ah = st. The pressure now falls 
by expansion of the steam behind the low-pressure piston, the terminal 
pressure an in the high-pressure cylinder being equal to the pressure 
rm in the low-pressure cylinder at half-stroke. Cut-off now takes place 
in the low-pressure cylinder, and the steam expands behind the piston 
to ck = J ad = J bf, at which point it escapes to the condenser, when 
the pressure falls to the line of back pressure. 

The volume of a receiver is relative to the volume of the high- 
pressure cylinder for the best distribution of the steam, and for two 
expansions it should be five times the volume of the high-pressure 
cylinder. For triple expansion the first receiver should be six times 
the volume of the high-pressure cylinder; for the second receiver its 
volume should be four times the volume of the intermediate cylinder. 
The variation in the receiver-pressure will be greater for a small 
receiver than for a large one, and also depend upon the initial pressure 
for any proportional size. 

As an illustration of the line of pressure in the receiver of a cross- 










306 


COMPOUND ENGINES 


compound engine with cranks at 90 degrees and cylinder proportions 
1 to 4, the diagram (Fig. 290) represents the general conditions. In 
the normal running of the engine with the cut-ofl in the high-pressure 
cylinder at one-half and in the low-pressure cylinder at one-fourth 
stroke, the pressure will increase in the receiver from the opening of 

the exhaust in the high-pressure 
cylinder at j until the valve of the 
low-pressure cylinder opens at 1, 
then falls until the cut-off of the 
low-pressure cylinder takes place 
at m, then rises until the high- 
pressure stroke is completed at 
n, and the next exhaust repeats 
the pressure-curve from j to 1. 
With the cut-off at half-stroke in each cylinder, the pressure lines lm 
and mn will be extended, each to the half-length of the stroke. 

In Fig. 291 are shown the relative position of the pistons at exhaust 
in the high-pressure cylinder and cut-off at half-stroke in the low- 
pressure cylinder—when the receiver-pressure is low, as in the left- 
hand figure—and at the moment of cut-off in the high-pressure cylinder 
and valve-opening in the low-pressure cylinder, when the receiver- 
pressure is high, as in the right-hand figure. 


M 



- -JG 

i 

i 

k 

i 

i 

i 

i 

i 

i 

!i 

i 

j p _• 

j i 

P n - 

: I n 

i 

1 1 

1 

_J 


L 


Fig. 290.—Diagram of receiver-pressure. 



Fig. 291.—Diagram of pressures in receiver, variable. 


The economy of reheating the steam in the receiver has not been 
satisfactorily defined by experiments made in Europe and the United 
States for this purpose. In a series of trials in England for reheating 
the steam within the receiver by a copper helical coil, negative results 
were obtained in nine-tenths of the trial runs. The conclusions 


















































COMPOUND ENGINES 


307 


arrived at by these trials were that the influence of the reheater was 
as follows: 

(a) Reducing the amount of condensation in the receiver. 

(b) Raising the receiver-pressure. 

(c) Raising the mean pressure throughout the engines. 

(d) Increasing the speed of revolution of the engines. 

(e) Increasing the dryness of the steam acting in the low-pressure 
cylinder. 

These may be ranked as effects which are in themselves favorable 
to economy. 

The influence of the reheater was found, however, equally marked 
in effects which were detrimental to economy, namely: 

(a) Lowering the mechanical efficiency of the engine. 

(b) Increasing the steam-consumption per horse-power developed. 

Experimental tests in the United States have added no positive 

economical results by reheating, over a thorough felting of the receiver 
and connecting-pipes. 

The use of superheated steam now coming into consideration and 
practice for all conditions of expansion, is of such importance in the 
economy of multicylinder engines for both land and marine service, 
that reheating in receivers will no doubt be left in its experimental 
stage in deference to the better economy of superheat. 


CHAPTER XVIII 


TRIPLE- AND QUADRUPLE-EXPANSION ENGINES 


The increased efficiency due to a greater range of expansion in the 
triple and quadruple effect from high pressures has brought steam- 
power to its highest degree of usefulness and economy. It is but 
a few years since, in the memory of old engineers, that a 10-per-cent, 
thermal efficiency was good practice; but improvements in metallurgy 
and the mechanic arts—which have made possible great advances in 
steam-pressure and its multiple expansion—together with the progres¬ 
sive experience in design, have more than doubled the power-economy 
of former years and brought the thermal efficiency up to 23 per cent, 
and the mechanical efficiency to 95 per cent., and possibly more. It 
is claimed that less than 1 pound of coal per indicated horse-power 
per hour has been obtained in test trials. 

The amount of steam or its equivalent per indicated horse-power 
per hour varies with the pressure and cut-off at the higher pressures 
now in use; and its distribution in triple-expansion engines is shown 
approximately in the following table: 


Table XXXVIII. —Water-Consumption in Triple-Expansion Engines. 



Initial Pressure by Gauge. 

Cut-off, 
per cent. 

High-pres¬ 
sure cylin¬ 
der, 

pounds. 

Interme¬ 
diate-pres¬ 
sure cylin¬ 
der, 

pounds. 

Low-pres¬ 
sure cylin¬ 
der, 

pounds. 

( 

120 

37.8 

1.3 

30 < 

140 

43.8 

2.8 

( 

160 

49.3 

3.8 

( 

120 

38.8 

2.8 

40 1 

140 

45.8 

3.9 

( 

160 

51.3 

5.3 

( 

120 

39.8 

3.7 

50 \ 

140 

46.8 

4.8 

{ 

160 

52.8 

6.3 


308 


Mean Effective Pressure, or 
Above Vacuum. 


High-pres¬ 
sure cylin¬ 
der, 

pounds. 

Interme¬ 
diate-pres¬ 
sure cylin¬ 
der, 

pounds. 

. 

Low-pres¬ 
sure cylin¬ 
der, 

pounds. 

Peed-water 
per I. H.-P. 
per hour, 
pounds. 

38.5 

17.1 

6.5 

12.05 

46.5 

18.6 

7.1 

11.4 

55.0 

20.0 

8.0 

10.75 

51.5 

22.8 

8.6 

11.65 

59.5 

23.7 

9.1 

11.4 

70.5 

25.5 

10.0 

10.85 

60.5 

26.7 

10.1 

12.2 

70.5 

28.0 

10.8 

11.6 

82.5 

30.0 

11.8 

11.15 




























309 


TRIPLE- AND QUADRUPLE-EXPANSION ENGINES 

The lecoid of a test of a high-duty triple-expansion pumping- 
engine of the Allis-C halmers vertical type, lately erected at the St. 
Louis water-works, is worthy of reference for its showing of thermal 
and mechanical efficiency. 


RESULTS OF DUTY TEST. 


Duration of test. 

Diameter of cylinders. 

Stroke of engine. 

Diameter of plungers. 

Average steam-pressure at engine. 

Average first receiver-pressure. 

Average second receiver-pressure. 

Average vacuum-pressure by cards. 

Average barometer-pressure. 

Average net head pumped against. 

Average revolutions per minute. 

Piston-speed per minute.. 

Total water pumped. 

Total water received from engine. 

Average moisture in steam. 

Indicated horse-power. 

Delivered horse-power. 

Per cent, friction. 

Average moist steam per indicated horse-power 

per hour. 

Average dry steam per indicated horse-power 

per hour. 

Average British thermal units per indicated 

horse-power per minute. 

Mechanical efficiency. 

Duty per 1,000 pounds of steam. 

Duty per 1,000,000 British thermal units. 

Thermal efficiency. 


24 hours. 

34 inches, 62 inches, and 94 inches. 
72 “ 

33 i “ 

140.24 pounds. 

26.36 
2.77 “ 

13.21 
14.46 “ 

238.2323 feet. 

16.539 
198.44 feet. 

20,070,690 gallons. 

220,129 pounds. 

0.13 per cent. 

865.23 horse-power. 

842.69 “ 

2.60 per cent. 

10.60 pounds. 


10.59 


it 


201.39 British thermal units. 
97.4 per cent. 

181,068,605 foot-pounds. 
158,851,000 “ 

21.06 per cent. 


As the multicompounding of steam-expansion enables the fullest 
advantage to be taken of the expansion from the highest pressures 
available—by reducing the range of temperature in any one cylinder 
and its initial condensation, and by utilizing its reevaporation in a 
succeeding cylinder—as also the economy due to the greater total 
range of temperatures with the lesser extreme strains in the mechan¬ 
isms—this system of steam-power has been brought to apparently 
the highest degree of perfection possible. 

In the diagram (Fig. 292) are shown the approximate divisions 
in a triple-expansion engine as between temperatures and absolute 



























310 TRIPLE- AND QUADRUPLE-EXPANSION ENGINES 

pressures from an initial pressure of 150 pounds absolute. These 
proportions may be varied to suit the equalized total pressure in each 
cylinder for any initial pressure proposed. 



Fig. 292.—Pressures and temperatures in triple expansion. 


The cylinder disposition and proportions in triple- and quadruple- 
expansion engines vary in a considerable degree, and are illustrated 
in the following figures: 

A high-pressure, intermediate-pressure, and low-pressure cylinder 
in line with a three-crank shaft, with cranks at 120 degrees (Fig. 293). 

A high-pressure, inter¬ 
mediate-pressure, and two 
low-pressure cylinders on a 
four-crank shaft at 90 de¬ 
grees, or alternating at 180 
degrees (Fig. 294). 

A quadruple - expansion 
engine with a high-pressure, 
consecutive first and second 
intermediate - pressure, and 
one low - pressure cylinder 
(Fig. 295). The quadruple 
is also built on the tandem 
model, with high and first 
intermediate tandem vertical and second intermediate and low tan¬ 
dem vertical in the marine service. 

The relative cylinder-volumes in these engines for high initial 


To Condenser 




Fig. 294.—Four-cylinder triple expansion. 































TRIPLE- AND QUADRUPLE-EXPANSION ENGINES 311 

pressure are from 2.3 to 2.7, and are divided so as to give about 20 
as the total number of expansions in a quadruple-expansion engine. 


To Condenser 



Fig. 295.—Four-cylinder quadruple expansion. 


The relative cylinder-volumes in some recently designed triple¬ 


expansion marine engines of over 5 
arranged for one high-pressure, 
one intermediate - pressure, and 
two low - pressure cylinders, are 
as 1: 2.7: 2.6 volumes. The latest 
practice, as shown in the designs 
of the United States Bureau of 
Steam - Engineering, for the en¬ 
gines of the North Carolina and 
Montana , has proportions of cylin¬ 
der-volumes of 1:2.64:2.71, with 
one high-pressure, one interme¬ 
diate-pressure, and two low-pres¬ 
sure cylinders in triple-expansion 
engines, and with piston-valves for 
all the cylinders, there being one 
piston-valve for the high-pressure 
cylinder and two each for the 
others. 

The illustrated details of these 
engines are shown in Figs. 296, 297, 
and 298, and represent results of 
design from the latest ideas for 
compactness and large power for 
war-ships which consist of two en- 


000 horse-power to each engine, 


L.P. CYLINDER 
LOOKING AFT 



Fig. 296.—End view of triple-expan¬ 
sion engine. U. S Navy. 











































































































































































































































































































Fig. 298.—Vertical section of four-cylinder triple-expansion engine. U. S. cruiser Montana. 



































































































































































































































































































































































































































































































































































































































314 TRIPLE- AND QUADRUPLE-EXPANSION ENGINES 

gines of 23,000 combined indicated horse-power, and with the following 
details of construction: 


Number of cylinders. One high-pressure, one intermediate-pres¬ 

sure, two low-pressure. 

Diameter of cylinders. 38J inches, 63J inches, 74 inches each. 

Stroke. 48 

Piston-valves for all cylinders. 

Initial steam-pressure.. 250 pounds. 

Boiler-pressure... 265 

Diameter of high-pressure piston-valve 24^ inches. 

Diameter of each low-pressure piston- 

valve. 27 “ 

Revolutions. 120 per minute. 

All main and valve cylinders have liners. Piston-clearance in all cylinders is § 
inch at the top and f inch at the bottom, with a probable average total clearance of 
about 2 per cent. 

The main shaft, crank-pins, cross-head pins, and piston-rods are hollow. 

Cranks of high- and low-pressure cylinders, adjacent, are 180 degrees; cranks of 
intermediate- and low-pressure cylinders, adjacent, 180 degrees; cranks of each 
pair, 90 degrees. 


A novel triple compound marine engine which may be used con¬ 
densing for a quadruple effect, is shown in front and cross sections 



Fig. 299. —Triple compound marine engine. 

in the two-part Fig. 299. The principal novelty is the three-part 
eccentric oscillating upon the crank-pin, and upon each of which a 


















































































TRIPLE- AND QUADRUPLE-EXPANSION ENGINES 315 

strap fixed to the piston-rod of each cylinder slides in ways parallel 
with each piston-rod. The throw of the eccentrics and that of the 
crank aie each equal to one-half the piston-stroke. The crank-eccen¬ 
trics are set at 120 degrees, as shown at a. The three-piston valves are 
directly connected by rods to thin straps on an angularly mounted 
cylinder that slides on the shaft by the hand-lever for forward, stop, 
or reverse motion. 

Piston-valves are used, taking the steam in the middle and ex¬ 
hausting at the ends. The steam passes from the first valve, through 
the triangular space between the cylinders, to the next valve-chest. 



Fig. 300.—Triple-expansion marine engine. Type of the steamer Minnesota. 

In Fig. 300 is shown a vertical section of a triple-expansion marine 
engine in which the high-pressure cylinder has a piston-valve, while 
the intermediate- and low-pressure cylinders have slide-valves. Pro¬ 
portion of cylinder's, 1, 5, 15 in area; stroke, 48 inches; crank positions, 
120 degrees; high-pressure cylinder, 23 inches diameter; intermediate 
cylinder, 51 inches diameter; low-pressure cylinder, 89 inches diameter. 

In Fig. 301 is shown a vertical section of a triple-expansion engine 
with a double tandem high-pressure cylinder in which its pistons act 
as valves to the intermediate cylinder. The object of this is to produce 

























































































































































































































































































316 TRIPLE- AND QUADRUPLE-EXPANSION ENGINES 


an arrangement of cylinders, steam-valves, and ports whereby the 
back pressure of the intermediate cylinder will not act as an opposing 
force on the high-pressure piston, and will also furnish full pressure 
of steam in the intermediate without increasing back pressure in the 
high. Steam enters the chamber a 3 , passes through an opening 
between the two piston-valves, which open to the upper piston, a, 
when it passes the bottom centre. The cut shows it in the act of 
closing. 

When working as a triple expansion the valve closes when the 
piston reaches the point b 2 , which allows the steam to enter cylinder 



Fig. 301.—Duplex-piston triple-expansion engine. 


B above piston b at full pressure, but the crank to cylinder A is on the 
quarter where it moves at its highest speed, while the piston b moves 
down. It will also be seen that lower piston a reaches the top of its 
cylinder at the same time, but instead of being in a position to exhaust 
as in the upper one, it will be in the position to receive through lower * 
port a 9 , valve a 5 having moved down far enough to open. The pistons 
a, a start, on the return-stroke, with a reversion of valve-movements. 
It is a curious study in steam-pressure interchange from piston port 
opening. 



























































































































CHAPTER XIX 


THE STEAM-TURBINE 

The steam-turbine, like the reciprocating engine, lias a history 
with an inception much earlier than that of steam-expansion, and 
is coeval with the knowledge of steam as a power possibility. The 
Heron steam-motor was a reaction-turbine of which there have been 
several models described in the early accounts. After nearly 1,800 
years since the introduction of Heron’s eolipile Branca brought out, 
in 1629, an impulse-wheel in which a jet of steam impinged upon 
the flat vanes of a wheel. The principle of expansion had not yet 
dawned. 

In the later years of the eighteenth century the principles of 
turbine-action came to an experimental stage, and Watt, Ericsson, 
Perkins, and others made trials with steam-turbines without per¬ 
manent results. Up to 1901 no less than four hundred patents were 
issued in England on the subject of steam-turbines. In 1843 Pilbrow 
patented a stage-expansion steam-turbine, and Wilson, in 1848, 
patented the first radial-flow turbine, which in design anticipated 
the Dow radial-flow turbine. 

In the United States the reaction-engine of William Avery had a 
few years of successful operation. Its rotor consisted of two hollow 
arms, thin and sharp like sword-blades, mounted on a hollow axis, 
and revolving in a dished-disk chamber. A small orifice, J X} inch, 
opened on the back of each blade, at the extreme end. One of 
its drawbacks, as claimed, was the friction-wear on the blades in 
cutting the exhaust-steam in the chamber. 

The author’s experience with an Avery turbine, erected in Buffalo, 

N. Y., in 1833 by his father, showed that at 1,000 revolutions per 

minute the stuffing-box on the hollow shaft could not be kept tight 

with the method of packing then in use, and that the oil in the journals 

and stuffing-box burned or baked by the heat of the steam and friction, 

and cut the bearings. Hemp and winter-strained sperm-oil were the 

317 


318 


THE STEAM-TURBINE 


best materials in those days for packing and lubrication. The turbine 
was soon replaced by a reciprocating engine. 

The Parsons type first took practical form about 1884, and the 
De Laval type in 1883, since which time the progress in design and the 
improvement in the machinery of construction have brought both 
types to their present efficiency and power. 

In both the De Laval and Parsons steam-turbines power is gener¬ 
ated by the impact of a jet of steam upon buckets on the periphery 
of a revolving disk. The essential differences between the two types 
of motors are these: The De Laval turbine has a single disk with 
several steam-jets or nozles. The nozles have divergent apertures 



in which the expansion of the steam takes place. The single turbine- 
disk revolves at a high rate.of speed, say from 10,000 to 30,000 revolu¬ 
tions per minute, according to the size of the motor, this speed being 
reduced to about one-tenth on the main shaft by means of accurately 
cut spiral gears. 

The Parsons type of turbine, on the other hand, has a series of 
disks mounted upon a common shaft and alternating with parallel 
blades fixed within the casing of the shaft. There are buckets, or 
cups, upon both the revolving disks and the fixed blades, the fixed 
buckets being reversed in relation to the moving cups. The steam, 
admitted first through a set of stationary blades or buckets, impinges 
at an angle upon the first rotating disk and imparts motion, passing 
thence through another set of fixed blades to the second disk upon 
the main shaft, and thus through the entire series of alternately 

























THE STEAM-TURBINE 


319 


fixed and rotating buckets. The area of the passages increases progres¬ 
sively to correspond with the expansion of the steam as it is used 
on the successive disks. The expansion of steam is accomplished in 
the turbine instead of in the nozle, as in the De Laval motor. The 
buckets in a given size of Parsons turbine number about 3,000, as 
against about 350 in a De Laval motor of the same size. 

The efficiency of the steam-turbine varies according to conditions, 
just as the economy of the reciprocating engine is similarly affected. 

Friction is reduced to a minimum in the steam-turbine, owing to 
the absence of sliding parts and the small number of bearings. In 
one type there are practically but two bearings. The absence of 
internal lubrication is also an important consideration, especially 
when it is desired to use condensers. 

As there are no reciprocating parts in a steam-turbine, and as a 
perfect balance of its rotating parts is absolutely essential to its suc¬ 
cessful operation, vibration is reduced to such a small element that 
the simplest foundations will suffice, and it is safe to locate steam- 
turbines on upper floors of a factory if this be desirable or necessary. 

The perfect balance of the moving parts and the extreme simplicity 
of construction tend to minimize the wear and increase the life of a 
turbine and at the same time to reduce the chance of interruption in its 
operation through derangement or damage of any of its essential parts. 

Although hardly beyond the stage of its first advent in the motive- 
power field, the steam-turbine has met with much favor, and there is 
promise of its wide use for the purposes to which it is particularly 
adapted. At present, however, its uses are restricted to service that 
is continuous and regular, its particular adaptability being for the 
driving of electrical generators, centrifugal pumps, ventilating fans, 
and similar high-speed work, especially where starting under load is 
not essential. 

Steam-turbines are now being built in the United States in all 
sizes up to 5,000 horse-power. Their use abroad covers a longer period 
and has become more general. 

The application of the steam-turbine to the propulsion of ships 
has produced surprising speed results. The Turbinia, in which the 
first experiments were tried in England, was a vessel 100 feet long, 
9 feet beam, 3 feet draught, and 44 tons displacement. As finally 
equipped this vessel attained a speed of 34J knots at Spithead in 1897, 


320 


THE STEAM-TURBINE 


with about 2,300 indicated horse-power. The torpedo-boat destroyer 
Viper , subsequently built for the British Admiralty, was 210 feet long, 
21 feet beam, and 350 tons displacement, and a speed of 30.858 knots 
was developed. 

The arrangement of nozles and buckets in the De Laval type of 
turbines has been made with nozles impinging on buckets across the 
periphery of the wheel, as shown in Fig. 303. The nozles are of the 



Fig. 303.—Peripheral bucket-turbine. 


expanding type, as shown in Fig. 123, from which the jets of steam 
impinge on the edge of curved buckets of the Felton type and dis¬ 
charge at the sides into the surrounding chamber. The long, slender 
shaft shown in the cross-section is to take up the unbalanced vibration 
of the disk. This model has not been credited with economical success. 

The side-nozle turbine, with a number of nozles impinging upon 
the side at an angle of from 15 to 20 degrees against lunette buckets, 
and exhausting at the other side to the atmosphere or to a condenser, 
is the De Laval type (Fig. 304). 

The wheel shown in Fig. 305 consists of a steel disk carefully 
balanced, and in form is very thick at the centre and made thinner 
as the outer edge is approached, a rim being formed at the edge, in 
which the buckets are mounted. A hub is formed on either side at 
the centre, in which is mounted the shaft, as shown. The shaft is 
formed of two separate pieces in the larger sizes, this form and method 
of mounting having proved to be the most flexible. The buckets 
are separate forgings of steel, held in the wheel by a bulb-shank 
fitting into a corresponding slot milled in the wheel. 

This shank is made a driving-fit, which serves to hold the buckets 






















































THE STEAM-TURBINE 


321 


in place. The surface of these buckets against which the steam issues 
is not finished, but retains the hardened scale formed by forging, 



necessary, they can be made at small expense and in a very short 
time. The nozles are made of bronze, and so designed for the different 
steam-pressures and vacuums that they permit the free expansion of 
the steam. When properly proportioned for a given initial and ter¬ 
minal pressure, the steam as it leaves the ends of the nozles assumes 
a parallel form of jet, and for this reason it is not found necessary 
to place the nozles close to the buckets, the loss through dissipation 
of energy between them being so small that it can be ignored. The 
amount of divergence in the nozle varies considerably for different 
initial and terminal pressures. As the nozles do not really confine 
the steam, but simply prevent outside influences from affecting the 
free expansion, there is no wear on them, and they last for years. 
As the steam is expanded in these nozles to the exhaust-pressure 



Fig. 304. —Side-nozle De 
Laval turbine. 


Fig. 305.—Section of De Laval turbine. 


under which the turbine operates and before coming in contact with 
the wheel, the pressure on both sides is the same, thereby preventing 
any end-thrust, and the acting and reacting forces of the steam as it 
strikes and leaves the vanes of the wheel are substantially the same, 
owing to the shape of the buckets and the angle at which the steam 
strikes them. 

The turbine-wheel revolves on its own centre of gravity by means 
of the flexible shaft mounted on bearings, and the floating bearings 




























322 


THE STEAM-TURBINE 


are really metallic packing, preventing the leakage of exhaust-steam 
when running non-condensing, and the entrance of air into the exhaust- 
chamber when operated condensing. The steam, after passing through 
the wheel, goes direct to the exhaust-pipe in the exhaust-chamber, 
the space on either side of the wheel being in free communication 
with this exhaust-chamber. As the rotative speed of the turbine- 
wheel is high it is necessary to have some means of reduction in order 
to apply it at low speeds, and this is accomplished by means of double 
spiral gears of small pitch. 

The system of governing consists of a balanced double-beat poppet- 
valve, controlled by a governor of extremely simple design and of the 



Inches Vacuum 

Fig. 306.—Turbine-efficiency with increase of vacuum. 


centrifugal t}^pe. 

The steam in this type of turbine performs its work by utilizing 
the velocity-energy of the steam by expanding it before reaching the 

moving or working part 
of the machine. This 
is done through the 
agency of nozles of defi¬ 
nite design, so placed as 
to direct the steam, af¬ 
ter it has been expand¬ 
ed, against the vanes 
or buckets of a wheel 
mounted on a flexible 
shaft with which it ro¬ 
tates. With these features understood the simplicity and power of 
the turbine can be fully appreciated, the unusual capacity for so small 
a machine being due to the great speed at which it rotates. (See 
Chapter X on nozles and steam-velocity.) 

The tremendous velocity which steam assumes in expanding from 
ordinary boiler-pressures to a vacuum—3,000 to 4,000 feet per second 
or 35 to 45 miles per minute—makes the use of a single wheel impracti¬ 
cable for turbines of large power. The stresses set up in the material 
of the wheel by centrifugal force prevent the employment of the 
peripheral speeds necessary for a satisfactory efficiency, and, except 
in a few cases, gearing is necessary to reduce the speed to a point 
where direct connection can be adopted. 

The diagram (Fig. 30G) shows the decrease in pounds of steam used 































Connected to a multipolar dynamo through double spiral gears, 1 to 10; 266 B. H. P., 155 pounds steam-pressure (using 17 pounds steam 

per B. H. P. hour); vacuum, 25.5 inches; 9,000 revolutions per minute. 










































































































































































































































324 


THE STEAH-TUllBINE 


per kilowatt hour and the percentage increase in efficiency by an 
increase of vacuum in a steam-turbine. It shows the value of a high 
vacuum. 

One reason why the vacuum is of particular value to a turbine is 
the reduction which it effects in the windage. A top will spin for a 
remarkably long time in a vacuum. If it had to spin in an atmos-* 
phere of compressed air or high-pressure steam, its motion would 
last for a comparatively shorter time. At the high speed at which 
the turbine is run the frictional resistance in the exhaust-pressure 
steam must be considerable, but in the less dense atmosphere of the 
vacuum much less of the energy absorbed is used in overcoming 
friction, and adding to the resulting power of the motor. 

In Fig. 307 is illustrated a recent plan of a De Laval steam- 
turbine with a double compensating spiral gear and connection to 
a multipolar dynamo. 

We illustrate some of the many forms or models in which experi¬ 
mental trials have been made that have, as far as the author knows, 
not brought out economical results in their practical development. 
Fig. 308 shows two views, and a section of the blades, of a Dow steam- 
turbine, in which two disks fixed to a shaft have on their face a series 
of circular grooves and tongues, meshed with a pair of fixed disks 

with grooves and tongues, as 
shown in the small section. 
The tongues on the revolving 
disks are cut across at short 
distances in a slanting direc¬ 
tion. The tongues on the sta- 
tionary disk are cut in the 
opposite direction. The steam 
passes to the centre hub, and 
is forced through the openings 
across the tongues, giving motion to the disks and shaft. The radial 
passage of the steam through blades of varying velocity seems a bar 
to efficiency. 

Another curious modification in construction, the Wilkinson 
steam-turbine (Fig. 309), consists of two rim-pocketed disks running 
against the disk-surfaces of a shell with oblique steam-ports. The 
disks are feathered on the shaft, and held against the faces of the shell 



Fig. 308.—Dow steam-turbine. 

























TOE STEAM-TURBINE 


port 

OZr) 


and the steam-pressure by springs. A groove around the shell opposite 
the pockets allows the steam to pass around to the exhaust-pipes. 
Ihe shape of the steam-pockets and -ports, m, n, in the rims of the 


disks is shown in the section at the right. 

An experimental turbine by Parsons of the radial impulse type is 
shown in big. 310, in which a series of disks are fixed on a shaft with 



Fig. 309. —Wilkinson steam-turbine. 



Fig. 310.—Parsons steam-turbine, 
early type. 


intersecting disks on the shell. The face of the shaft-disks has several 
small blades set at an angle with the radius. The outside fixed 
disks have a similar set of blades interlocking with the revolving blades 
and set at a contrary angle. The steam passes from the valve to the 
inner edge of the first fixed disk, then outward through the blades, 
and returns through the vacant space of the next pair and outward 
again. 

This form of the Parsons turbine is an improvement on the prin¬ 
ciple of the Dow type by multiple effect, but is still inefficient as 
compared with the later types of axial steam-flow. 


THE MULTISTAGE STEAM-TURBINE — 

PARSONS TYPE 

In Fig. 311 is shown a sectional view of one of the earlier models 
of the Parsons turbine. The steam is admitted to the chamber A, 
encircling the cylinder, from the governor-valve, and passes along 
to the right through the turbine-blades, which deflect it in one direc¬ 
tion, thence striking the moving blades of the turbine, which deflect 
it in the opposite direction, and so on. In this way the current of 

































































































326 


THE STEAM-TURBINE 


steam impinging upon the moving blades drives them around. The 
areas of the passages increase, progressing in volume corresponding 
with the expansion of the steam. On the left of the steam-inlet 
are revolving balance-pistons, C, Ci, C 2 , one corresponding to each 
of the cylinders in the turbine. The entering steam at A presses 
equally against the revolving part of the turbine and against the 
first balancing-piston. When it arrives at the passage E it presses 
against the next larger section of the revolving part of the turbine 
and also against the next larger balancing-piston, connection between 
the two being secured by the passage F. Similarly, the passage G 
permits the balancing of the largest section of the turbine. By a proper 
arrangement of these balancing-pistons there is no end-thrust upon the 



Fig. 311.—Parsons steam-turbine. 


turbine-shaft at any load or steam-pressure. The thrust-bearing at 
H, on the extreme left, is to take care of accidental thrusts that may 
arise and also to retain the alignment of the shaft accurately so as 
to secure the correct adjustment of the balance-pistons. 

Since these balance-pistons never come in mechanical contact 
with the cylinder in which they turn, there is no friction. The thrust¬ 
bearing is made of ample size and is subject to forced lubrication. 

The pipe K connects the chamber back of the balance-pistons 
with the exhaust-outlet, so as to insure the pressure being equal at 
the two ends of the turbine. 

The‘bearings J, J are peculiar in construction. Each consists of a 
gun-metal sleeve prevented from turning by a loose-fitting dowel-pin. 
Outside of this are three cylindrical tubes having a small clearance 
between them. These small clearances fill up with oil and permit a 















































































































THE STEAM-TURBINE 


327 


slight vibration of the inner shell, while at the same time restraining 
it from too great a movement. The shaft therefore actually revolves 
about its axis of gravity instead of its geometrical axis, as would be 
the case with the bearings of the 
usual rigid construction. In case the 
shaft is a little out of balance the 
journal thus permits it to run slightly 
eccentric. The forms of the rotating 
and stationary blades are much like 
those of the Curtiss type, which are 
detailed in Fig. 312. 

The casing of the turbine is lined 
with disks of blades curved in reverse 
of the blades on the rotor; all of 
their surfaces are of approximately 
parabolic form, as shown in the cut. 

In Fig. 313 is represented a 
vertical section of the later Parsons turbine as built by the Westing- 
house Machine Company. The steam from the governor-valve V 
enters the neck of the rotor at A through ports around the shell, and 
passes to the left through the successive disks of stationary and 
revolving blades. The area of the passage between the blades is 
continually enlarged to meet the increasing volume of steam by its 
expansion, by increasing their length, and in stepping up in area by 
enlarging the diameter of the rotor, until finally it is exhausted into 
the chamber B and into the condenser. 

By this traverse of the steam there are the initial pressure upon 
one end of the series of rotating blades and a vacuum on the other, 
the difference tending to press the rotor toward the low-pressure end. 
This thrust is counterbalanced by a series of balancing-disks, P, P, P, 
equal in diameter to the respective sections of the drum. The steam 
enters between the smallest of these disks and the first ring of blades, 
and tends to push the disk to the right as much as the blade to the 
left, and from the chamber, before each enlargement of the drum, 
an equalizing-pipe or -passage, E, leads to the corresponding balancing- 
disk. A similar pipe connects the vacuum-chamber with the back 
of the largest disk, so that the pressures are effectually balanced. 
The balancing-disks are finely grooved on the rims and run in the 




Fig. 312.—Stationary and running 
blades. 





















































































































































































































































































































































































































































THE STEAM-TURBINE 


329 

grooved pockets of the casing. A small thrust-bearing takes care 
of any incidental tendency to move endwise, and adjustment is pro¬ 
vided for the relative positions of the blades. 

The principle of action in this turbine is that the steam of the 
initial pressure is admitted upon one side of the smallest ring and, 
flowing through the spaces formed by the blades, impinges upon the 
first ring of rotating blades, giving them motion by its impact. But 
the pressure upon the exhaust side of the rotating blade is less than 
that upon its intake side, and the steam goes on expanding in the 
spaces between the blades and issues from them with a considerable 
velocity, adding its reaction effect to that of impact. Reversed in 
the next set of stationary blades, in which its expansion continues, it 
impacts upon the next ring of moving blades, and so on through 
the turbine, the space between the blades increasing progressively by 
their increasing length. 

The admission-port for steam is shown at S. A secondary governor- 
valve (shown at V s ) from the admission-port provides for admitting 
high-pressure steam directly to the second expansion stage when the 
turbine is to carry heavy overloads or if the vacuum fails from any 
cause. 

Regulation is accomplished by means of a constantly moving 
pilot-valve controlled by a fly ball-governor. The governor-levers 
are mounted on knife-edges instead of pins, to secure sensitiveness. 
Speed may be regulated while the governor is in motion. This is 
particularly useful for synchronizing the speed of alternating-current 
machines operated in parallel and for adjusting their differences of 
load when so operated. 

The pilot-valve controls the admission-valves, which are of the 
balanced vertical lift poppet type. 

Steam is admitted to the turbine in puffs by means of a cam on 
the governor and a spring-operated piston, a steam-relay making 
about three impulses per second. 

High-pressure steam is admitted at all loads, and the admission- 
steam is not throttled in proportion to the load. At full load the steam- 
puffs merge into an almost continuous flow. 

The governor- and pilot-valve are operated by a worm-gearing 
on the main shaft. The pilot-valve has no “ inertia of rest,” and 
does not stick. 


330 


THE STEAM-TURBINE 


On the larger machines a speed-limit governor is arranged to in¬ 
stantly shut off the steam-supply whenever a predetermined limit 
of speed above normal is reached. 

Frictionless glands at the ends of the stator prevent the admission 
of air or the escape of steam. 

The rotating disks revolve within the stator with a close fit but 
not in contact. The adjacent surfaces are provided with frictionless 
packing-rings. These offer a devious path for the steam, and leakage 
past them is inappreciable. 

A flexible sleeve-coupling connects the turbine to its generator. 

Oil for the turbine- and generator-bearings is raised by a small 
plunger-pump from a main reservoir in the bedplate and circulates 
by gravity. It is cooled by water-coils. 

The Westinghouse-Parsons turbine utilizes the full steam-energy 
and does this at rotative speeds well within commercial requirements. 
These speeds do not exceed 3,600 turns a minute for the 400-kilowatt 
unit. For the larger units the number of turns is less. The steam 
is also robbed of all power of erosion by having its velocity gradually 
reduced as it passes through the turbine. 


Table XXXIX.— Gives the Efficiency-Tests of a 500-kilowatt, Westing¬ 
house-Parsons Turbine, and Shows the Relative Steam-Consumption 
for Saturated and Superheated Steam and for Varying Vacuum. 


Test. 

Load. 

Steam. 

Steam-Consumption. 

No. 

Proportion 

of 

capacity. 

B.H.-P. 

Pressure, 

pounds. 

Quality. 

Vacuum, 

inches 

absolute. 

Total 
pounds 
per hour. 

Pounds per 
B. H.-P. 
hour. 




Saturated steam. 



1 

l 

1 . 

396.0 

151.2 

99.47 

28.03 

5,908 

14.92 

2 

3 

4 

584.3 

152.6 

99.50 

28.03 

8,211 

14.05 

3 

Full 

762.3 

153.2 

99.45 

27.70 

10,429 

13.68 




Superheated steam 



5 

Full 

763.9 

153.3 

. 

28.00 

9,334 

12.22 



(105.2° F. superheat.) 




Reduced vacuum. 



6 

Full 

722.9 

148.8 

99.53 

26.03 

10,781 

14.91 

4 

H 

1,145.5 

142.6 

99.58 

26.30 

10,429 

15.08 

7 

Full 

678.7 

148.9 

99.73 

24.10 

10,764 

15.86 



















































331 


THE STEAM-TURBINE 

An efficiency-test of a 1,250-ldlowatt turbine of the above type 
consumed -7 pounds of steam, without vacuum or superheat, per 
brake horse-power and 890 brake horse-power load, and 24 pounds 
at 1,260 brake horse-power load, 150 pounds initial pressure. 

The governor-valve used on the Parsons turbine varies in con¬ 
struction somewhat with the different builders of steam-turbines, 
and may be called properly a relay or vibrating valve. It consists 
essentially of a double-beat or balanced valve operated by a small 

piston and spring, with its opening and vibration both operated from 
the governor. In Fig. 

314 is illustrated the 
vibrating valve-gear, in 
which the double-beat 
valve V is shown closed. 

The spindle of this valve 
projects upward and car¬ 
ries a small piston, B, 
which is enclosed in a 
cylinder and held in its 
lowest position by means 
of a spiral spring, F. In 
the bottom of the cylin¬ 
der there is a small hole, 

0, through which steam 
flows under the piston B 
when the main valve E 
is opened, so that the 
piston is lifted up and at the same time the double-beat valve V 
is opened. Steam can now flow into the turbine at A. The double¬ 
beat valve V will now remain open as long as there is steam below 
the piston B. In order to allow this steam to escape from time 
to time, there is another port-hole, D, which is considerably larger 
than the steam-inlet 0. The port-hole D is kept closed by means 
of a small piston, G, which is periodically lifted in a regular jigging 
motion by the eccentric X, which is directly connected to the gov¬ 
ernor-spindle, so that steam escapes from the cylinder at D through 
the pipe H. The spring S now overcomes the piston B, which descends, 
thereby closing the double-beat valve V. Shortly after, the piston G is 



Fig. 314. —Vibrating valve-gear of the Parsons 
steam-turbine. 




























































































332 


THE STEAM-TURBINE 


again pushed downward and the hole I) closed, whereupon steam again 
forces up the piston B, so that the double-beat. valve is once more 
opened. As the motion of the piston G is obtained from the eccentric 
X, the number of lifts bears a fixed ratio to the speed of the turbine, 
and the number of gusts of steam is therefore also proportional thereto. 
The general disposition of the governor-gear is clearly shown in the cut. 



Fig. 315 shows indicator-diagrams illustrating the variation of 
pressure due to the vibration of the relay or double beat valve at the 
steam-entrance A in Fig. 314. The abscissa or frequency are a func¬ 
tion of time, and their length depends upon the speed for which the 
indicator-gear was set. 

THE CURTISS STEAM-TURBINE 

The Curtiss type of steam-turbine is assumed to be a combination 
of the principles of action of the De Laval and Parsons types, in that 
the first impact of the steam is from a series of several expanding 
nozles, in groups of two or three, at equal distances around the revolv¬ 
ing wheel, directly upon the revolving blades, and from a reaction by a 
fixed-blade disk, and in that a further impact occurs upon the second 
revolving wheel-blades, the steam thus expanding through two or three 
stages, and terminating in the condenser. The vertical arrangement 
of the shaft, with the horizontal plane of motion, is one of the dis¬ 
tinctive features of the Curtiss turbine. 

In Fig. 316 is shown an elevation of a two-stage turbine with three 
sets of nozles equally divided around the periphery of the wheels. 
Each of the five or more nozles in each set is of the expanding form, 
with rectangular apertures extending across the wheel-blade width. 
Steam enters through the series of nozles, forming a broad belt of 






THE STEAM-TURBINE 


333 


steam, and the quantity admitted is regulated by a series of poppet- 
valves, one for each nozle. Regulation is effected by opening or clos¬ 
ing these valves automatically, and for fine regulation, involving a 
less quantity of steam than flows through any one nozle, throttling 
in one nozle is resorted to. In the 5,000-kilowatt turbine there are 
three sets of these nozles, spaced at 60-degree angles, and the steam 
passes through three sets of blades into an intermediate receiver, 
in which the pressure is approximately that of the atmosphere. 
Thence it passes through a second set of guide-passages, or nozles, 
which expand the steam near¬ 
ly to the vacuum-pressure, 
and the velocity of the steam 
is abstracted by three more 
sets of blades. The second 
row of nozles occupies the 
whole circumference of the 
wheel, to allow for the great 
volume of the low-pressure 
steam. 

In Fig. 317 are shown an 
outside half-view and half- 
section of the Curtiss turbine, 
with a four-stage expansion 
and two sets of multi-nozles. 

The path of the steam through 
the turbine is indicated in the 

drawing, which show s also the jq G g^g—Two-stage Curtiss turbine, 
four stages into which the 

turbine is divided. From the steam-chest the steam passes through 
poppet-valves to the nozles which direct it upon the vanes of the first 
of the moving wheels of that stage, then to the stationary guide-vanes, 
then to the second moving wheel, from which it passes over the second 
set of guide-vanes to the third moving wheel. At this point the steam 
enters the third set of guide-vanes and undergoes a similar operation, 
finally passing out at the bottom of the turbine into a condenser. 

In the first stage the nozles occupy but one-sixth of the circum¬ 
ference, and are divided into two equal sets in the turbine illustrated. 
In the 500-kilov T att size the nozles are all grouped together; in inter- 



































































































334 


THE STEAM-TURBINE 


mediate sizes they are divided into two, and in the 5,000-kilowatt size 
into three, groups equally spaced. The first intermediate guides in 
all machines are grouped in the same manner as the nozles and occupy 
the same circumferential length. In the second and third stages 
the nozles and intermediate guides generally occupy the entire circum¬ 
ference. 

The nozles are cored or cut passages in a cast plate, forming, in 
the first stage, the bottom of a steam-chest over the periphery of the 



Fig. 317.—Half-section of Curtiss 
turbine. 


turbine-wheel. The nozles of the 
second stage are secured to a dia¬ 
phragm separating the two stages. 
The nozle-openings of this stage are 
adjusted to maintain the pressure- 
relation between the two stages, or 
to shut off the second stage entirely 
when the turbine is run non-con¬ 
densing. This adjustment, which 
remains permanent for an approxi¬ 
mately fixed condition of load, is 
secured by means of a register-ring 
rotating through a small angle. The 
nozles of each stage are so propor¬ 
tioned that the steam, when it 
strikes the blades, has a pressure 
but slightly above the exhaust, and 
this pressure is reduced in passage 
through the wheels and guides to 
about the exhaust-pressure. 

In Fig. 318 is shown the arrange¬ 
ment of the steam-chest, valves, 
nozles, and moving and stationary 
blades for a three-stage turbine. The 
most vital points in a steam-turbine 


are the buckets, since they, and the spaces between them, must be 
shaped exactly right to give the correct direction of flow and highest 
mechanical efficiency, and also to provide for the progressive expansion 
of the steam. The buckets of the Curtiss turbine are cut out of the 
solid metal by special bucket-cutting machines. For the smaller sizes 














































































































































THE STEAM-TURBINE 


335 


of wheels the blades are cut from the disks comprising the wheels, and 
for the larger sizes the buckets are cut from segments of steel and 
then bolted around the periphery of the disks. 


STEAM CHEST 
r-i 


V//. 

I 

I 

I 




yA 


Mj 


m=\ 

m 

'iJm 




v// 


m _ 

i 


NOZZLE 



I<<R<<<<<<<<<<<<C. 
ERC(«<< «(«««<• 


MOVING BLADES 
STATIONARY BLADES 
MOVING BLADES 
STATIONARY BLADES 
MOVING BLADES 


NOZZLE DIAPHRAGM 



MOVING BLADES 

STATIONARY 

BLADES 

MOVING BLADE8 


STATIONARY 

BLADES 

MOVING BLADE8 


CG 


mm 


U<< <<<<M<<<< H<<4 




«««(«««««« 


I I 


I i 


Fig. 318.—Arrangement of nozles and blades. 


Fig. 319 shows a bucket- or blade-segment, with a rim of steel 
riveted on and enclosing the outer openings of the curved passages 
in the buckets. 



Fig. 319.—Bucket-segment. 


In Figs. 320 and 321 are shown the elevation and plan of the com¬ 
plete installation of the 2,000-kilowatt Curtiss turbine at the St. 
Louis Exposition. The plant consists of a two-stage turbine, with 
















































































































336 


THE STEAM-TURBINE 


two .sets of ten nozle-ports on opposite sides and an electric control 
of the nozle-valves; a small turbine-driven exciter-dynamo, a vacuum 



Fig. 320.—2,000-kilowatt Curtiss turbine and generator. 


pump, a hot-water pump, an oil-pump, and an air-cooler. The normal 
speed of the turbine and generator was about 800 revolutions per 
minute, with an initial pressure of 175 pounds. 

There are no oil-cups, and no hand-oiling is required, all lubrication 


TURBO- 


































































































































































































































































































































































































































































































THE STEAM-TURBINE 


337 


being performed by a circulating system, power for which is furnished 
by a steam-driven oil-pump capable of delivering 7\ gallons of oil 
per minute against a pressure of 500 pounds per square inch. This 
pressure is maintained below the step-bearing, while a baffler allows 
a small quantity of oil at a low pressure to rise to a small tank on the 
top of the machine, whence it flows by gravity to the top and middle 
guide-bearings. There is a combined reservoir and cooling-tank in 
this oiling system of 100 gallons capacity. Absolutely no cylinder-oil 
is used within the turbine, nor does any oil mingle with the steam. 

The most interesting of the auxiliaries is the 25-kilowatt direct- 
connected horizontal type turbine-driven exciter, making 3,600 
revolutions per minute and furnishing direct current at 125 volts. 
This machine is of the single-stage type, having three rows of buckets 



on the wheel and runs non-condensing. It is governed with a throt¬ 
tle-governor, and maintains a practically constant speed and voltage 
from no load to full load. It has a forced lubricating system of its 
own, operated by gear from the generator end of the shaft. 

In starting up either the large or small turbine, the operator 
merely opens wide the main steam-valve, after which both machines 
take entire care of themselves, whether running light or carrying a 
heavy, fluctuating load. 

In Fig. 322 is shown in section the slide-valve system of regulating 
the flow of steam to the vanes of a two-stage Curtiss turbine of recent 
model. 

































































































































338 


THE STEAM-TURBINE 


In Fig, 323 is illustrated a novel arrangement by which the buckets 
on each disk are doubled in effect, producing eight stages of impact 
and reaction in a four-disk turbine. The exhaust-steam from the 
first disk of two sets of running buckets and intervening stationary 
buckets is passed, through an outside chamber with automatic valves, 
to the second and third disks, and thence direct through the buckets 
of the fourth disk. The area of the buckets throughout the system 
is expanded by lengthening to meet the requirement of the expanding 
volume of the steam. 





Fig. 323.—Reenforcement in four-stage turbine by double buckets on each disk. 


For this construction the rim of each disk is made wide enough 
to receive the stationary-bucket sections and their clearance. The 
disk-buckets are flanged and bolted to each side of the disks. The 
stationary buckets are fixed in grooves in the shell. 

The vertical position of the shaft in the Curtiss turbine throws 
great weight upon the shaft-step, which with any ordinary form of 
step-bearing would become an insurmountable obstacle to this posi¬ 
tion of the turbine. 

In Fig. 324 is shown a section of the step and adjustments as de¬ 
signed for the Curtiss turbine. The bearing consists of two hard 
cast-iron blocks, one carried by the end of the shaft and fixed by 
dowels and key. The lower block is fitted to the follower, and is 


























































































THE STEAM-TURBINE 


339 


—| 


supported by a powerful screw driven by a wheel, and is provided 
with worm-gear for adjustment. 

This block is recessed to about half its diameter, and into this recess 
oil is forced with sufficient pressure to balance the weight of the whole 
revolving element. The amount 
of oil required is small. About 4 
gallons per minute is used in the 
5,000-kilowatt machine. A water 
circulation in the main step-block 
keeps all the bearings cool. 

The oil, after passing between 
the blocks of step-bearing, wells 
upward and lubricates a step-bear¬ 
ing supported by the same casting. 

This whole structure is inside the 
base, and a packing is used between 
the oil-chamber and the base, so 
that oil or air cannot get into the 
vacuum-chamber. A small steam- 
pressure is maintained between the 
sections of this packing, in order 
that these objects may be accom¬ 
plished with certainty. In many 

cases these same step-bearings have been operated with water instead 
of oil, in which case no packing is necessary, the water being allowed 
to pass into the base. 



Fig. 324.—Turbine-step. 


THE RATEAU STEAM-TURBINE 

The steam-turbine designed by A. Rateau and made principally 
in France and Germany, is a horizontal turbine of the axial-impulse 
type, with the blades of the same form as those of the De Laval, 
Curtiss, and Parsons models, but differing in constructive detail. 
The bucket-orifices are enlarged progressively, as in the Parsons and 
Curtiss turbines, by lengthening the blades of both elements. 

The revolving wheels are formed of disks of thin sheet steel, carry¬ 
ing cylindrical buckets on the periphery, these.buckets being riveted 
to a" band of steel welded to the disk. This gives a very light 












































































340 


THE STEAM-TURBINE 


and strong construction, maintaining its balance at all speeds. ^ The 
guide-buckets are fixed in circular diaphragms, secured at the pe¬ 
riphery in grooves cut in the interior of the turbine-case. There is 
thus left between the successive diaphragms a series of annular cham¬ 
bers in which the revolving wheels are placed. The shaft passes 
through bushings fitted in the diaphragms, there being but little 



play or clearance. Between the fixed and revolving portions of the 
turbine, however, the clearance may readily be made as much as 5 
millimetres, without injury. The main bearings of the shaft are 
outside the casing, a special form of stuffing-box being employed, 
assuring tightness against leakage. 

An ordinary compensated centrifugal governor is used to regulate 
the speed, acting by varying the pressure of the steam delivered to the 
turbine. By means of a by-pass in the main steam-pipe it is possible 
to deliver steam of full pressure both to the entrance of the turbine 
at A, and to a point in the machine nearer to the condenser, this en¬ 
abling a higher power than the normal amount to be produced by 
the machine, much in the same manner as a compound engine may 
be used with full-pressure steam in both high- and low-pressure 
cylinders. 










































































































































































































THE STEAM-TURBINE 


341 


T H E Z O E L L Y STEAM-TURBINE 

Among the many different types or models of turbines built in 
Europe, we illustrate in Fig. 326 a Swiss duplex turbine, constructed 
by Escher, Wyss & Co., of Zurich, the builders of the first Niagara 
water-turbines, a type since adopted by American builders. It is of 
the Zoelly design, and divided into two compartments, alike in detail, 
but one is adapted to a high- and the other to a low-pressure steam- 
range. 

The Zurich turbine is of the multistage impulse type, the expan¬ 
sion of steam taking place in the passages between the wheels, and the 
force on the moving wheels being exerted by impact of the rapidly 
flowing steam-jet. On the high-pressure wheels, steam is admitted 
to buckets around only part of the circumference, while on the low- 
pressure wheels the admission is to all buckets. The high- and low- 
pressure ends are mounted independently on a single base, connection 



between them being made by a pipe carried beneath the turbine. 
The main bearings are outside the wheel-cases, and are mounted on 
the base-plate independently. They are thus kept away from the 
heat of the steam, and are easily accessible for inspection and repairs. 

The wheels are built up of open-hearth steel disks, keyed to the 
shaft and having on the outer rim a ring fastened in such a manner 

























































































































































THE STEAM-TURBINE 


342 

that with the rim of the disk it forms a dovetailed groove. The 
buckets and spacers between them are held by tongues in this groove, 
and project radially from the rim of the disk. The buckets aie of 
nickel steel highly polished to reduce friction, as are also the disks. 

A point which is made by the designer is that the blades decrease 
in cross-section from their inner to their outer ends, so that the cen¬ 
trifugal force is kept very low, and the blades can safely be made 
much longer than if they were of uniform cross-section. Also the 
blades, which act as a cantilever-beam, are made strongest at the 
point where the bending moment due to steam-impact is greatest. 
The curve of the blades is such as is needed for the progressive ex¬ 
pansion of the steam. 

This special construction allows of running the wheels at a high 
rim-speed, thus reducing the number of stages needed in the turbine, 
which in turn allows of a shorter machine and of lower cost. The 

guide-wheels are placed 
between the revolving 
wheels and are carried 
from the outer casing. 
On account of the shape 
of the guide-blades, 
shown in Fig. 327, there 
is a considerable endwise 
pressure which is taken 
care of by using thick 
distance-pieces project¬ 
ing outside the radial 
blades of the moving wheels and transmitting the end-thrust from 
the guide-disks to the outer end of the casing. The general arrange¬ 
ment of wheels and guide-disks is shown in the section of the low- 
pressure end, and the detail of construction in the larger view. 
The pressure on the two sides of the revolving disks is in all cases 
equal, so that no end-thrust is produced. The governor is of the 
flyball type;, and operates a pilot-valve controlling the motion of a 
plunger, which in turn operates the main steam-valve, thus throttling 
the pressure of the steam. The water-pressure for operating this 
plunger-valve is furnished by an auxiliary motor. 

We cannot give space to all the types or models of steam-turbines 









































THE STEAM-TURBINE 


343 


in successful operation; some of them will no doubt become permanent 
in their special line of usefulness. They have come to stay, in har¬ 
mony with the reciprocating engine, which by its long and varied trial 
has standardized it for every use. 

THE ROTARY ENGINE 

In regard to the rotary type of steam-engine we find nothing 
worthy of illustration or description, and from many years’ experi¬ 
ence with their performance and lasting qualities, have found nothing 
as yet to recommend them, being inefficient and of short life; yet a 
few small ones are in use. We have left them to the tender mercies 
of their inventors and promoters. 

The Dake engine, now in use for small units of power, although 
called a rotary, is not of that type, but a combination of two rectangu¬ 
lar pistons, concentric and moving at right angles to each other, of 
which one is pivoted to a crank and shaft centring within a rectangular 
case. 

The contest for the survival of the fittest types of prime movers 
of motive power in the future will finally culminate in the success 
due to efficiency and durability in the various fields of their usefulness, 
and no one type can become universal. 

Nature’s elements, wind and water, with steam and confined 
combustion for power, are the only and real bases of our future pros¬ 
perity in the production of primary power, in which each is prominent 
in its own sphere of usefulness. 

THE STARTING AND OPERATION OF LARGE 

STEAM-PLANTS 

Much discussion has been published in technical journals in regard 
to the time required for starting large steam-plants of the recipro¬ 
cating and turbine types. We here give an excerpt from a published 
article by an engineer familiar with large steam-plants: 

“So much has been written about the sensitiveness of a rotating 
disk to the changes of temperature and the effects of unequal expan¬ 
sion that it is easy to imagine difficulties in the rapid start. The 
possibilities of an engine with a 62-inch low-pressure cylinder in 


344 


THE STEAM-TURBINE 


starting practically cold and coining up to synchronous speed are 
well understood. A station-manager would criticise an engineer 
who would open his throttle as fast as he dared without wrecking 
his piping system and let his machine jump into her work. One turn 
at a time on the throttle is about all that is considered safe, and even 
then a close watch is kept for groaning valves and cold back bonnets. 

“Every time the starting-valve is moved to increase the steam- 
flow the engine is allowed to take its full increment of speed, due to 
that particular throttle-position, before the supply-valve is moved 
a second time. There are ten large oil-cups, and frequently more, 
that must be opened and adjusted before the machine moves at all, 
besides whatever oiling is to be done about the air-pumps and other 
auxiliary apparatus. 

“Most engineers would consider ten minutes as rather a fast start 
and fifteen minutes as a more usual starting-period, including time 
taken for warming up; in fact, it may not be overstating the case to 
say that if it were known that an engine-driven plant were to be called 
upon in emergency for power and it were essential that the briefest 
possible time were to elapse between the call and the taking of the 
load, one or more engines would be kept in motion all the time, 
turning slowly and hot all over. 

“This question makes itself very prominent when the steam- 
station is operated as an auxiliary to a large source of high-tension 
power, which is itself in the construction stage and has a large over¬ 
load capacity of its own to carry, supplying all sorts of apparatus 
that use electric power, railway, lighting, and power circuits simulta¬ 
neously. 

“At such a time all sorts of accidents will happen to the high- 
tension water-driven plant, most of them due to the necessarily 
temporary character of many of the electrical connections. It takes 
months before an intricate system of wiring can be thoroughly relied 
upon, for it takes months before the temporary work of construction 
can be replaced. 

“The station under consideration is equipped with three Curtiss 
turbine-driven alternators, 40-cycle, 10,000 volts, each of 1,500 kilo¬ 
watts normal capacity. During the summer months the station is 
operated as an auxiliary to a water-power plant, taking all sudden 
overloads. 


THE STEAM-TURBINE 


345 


a A signal has been arranged, a f-inch whistle, so that it can be 
blown instantly should the power fail. A blast of that whistle 
means—cut in two turbines and bring the third up to speed. The 
load will be heavy, and all auxiliary apparatus must be in regular 
operation. 

“Each turbine has a surface-condenser, and there are three or 
four pumps to be started for each pair of turbines—one circulating- 
pump, one combined hot-well and feed-pump, one pressure-pump 
for the step-bearings, and one dry air-pump, all of which are motor- 
driven. The exciter is driven by a steam-engine and must be started 
also, for it supplies current to a portion of the auxiliary apparatus. 

“The boiler-room has steam up at all times, supplying a system 
for manufacturing purposes other than power, and slow fires are kept 
in enough boilers to make steam#needed for the normal load. Forced 
load means forced fires. The boilers have under feed-stokers, equipped 
with pressure-blast, and will respond quickly to a 50-per-cent.-excess 
call for steam. The operating force for this is about equivalent to 
a force for an engine-driven plant. Engineers and oilers, however, 
are busy about the building on construction work, installing new 
apparatus and taking such work as their regular occupation when 
the turbines are not running. 

“At the sound of the whistle the water-tender starts a blower 
on the extra row of boilers: all blast-dampers are opened up and all 
stokers are allowed to feed at the maximum rate. Each fireman 
dumps his free ash and bars over his red fire. 

“The man in charge of the coal-and-ash conveyer starts the 
pressure-pump for step-bearings. One of the turbine men starts the 
exciter which supplies current to the auxiliaries beside its field-current; 
a second turbine man starts the circulating-pump and then his turbine. 
The hot-well pump and the air-pump are started by the oiler. These 
movements take place simultaneously. The force is organized upon 
the lines that obtain in a fire-station; each man has his specific duty, 
and after performing it looks to see that there is nothing more for 
him to do. Only a few seconds elapse between starting the first 
pump and starting the first turbine. 

“The turbine-throttle is opened as fast as an 8-inch steam-valve 
can be opened without endangering the steam-piping system. It is 
not considered advisable to open the throttle-valve as fast as a mans 


THE STEAM-TURBINE 


340 

strength will permit; but if nothing unusual occurs in the pipe-line, 
sentiment does not spare the turbine. 

“One electrician attends to the switchboard and telephone. As 
soon as the machine approaches speed, the synchronizing system is 
cut in and the main switches are got ready. One and one-half min¬ 
utes will do all the work here outlined, including the time taken in 
mustering the crew from various parts of the building, itself not a 
trivial matter. 

“Manipulating an engine-regulator so that it shall be at a precise 
speed and at an exact phase relationship from some other machine, 
not more than part of a second removed from it, is no matter that 
can be hurried, and one minute is fast time on such work. But the 
whole thing, phasing-in and all, has been done in two and one-half 
minutes, including full load on the ♦turbine, which started from a 
standstill. 

“This performance has been gone through a great many times, 
and our record-book shows that out of 43 such calls, 10 starts were 
made in 24 minutes, IS in 3 minutes, and 15 in 34 minutes. 

“We have taken the time in a number of instances when all the 
auxiliaries have been in motion and it only remained to start the 
turbine and phase it in on the line; the only valves to open in such 
cases are the throttle and one small oil-valve. The two quickest 
starts have been made in forty-five seconds and seventy seconds, 
respectively, including phasing-in. Others range between one minute 
ten seconds and one and one-half minutes. The two quickest starts 
were made on a turbine which had stood for twenty-four hours with 
the throttle-valve shut tight, though there was a slight leakage past 
the seat. After the throttle-valve is off its seat it is not more than 
thirty seconds before the turbine is up to speed. A cross-compound 
reciprocating engine of the four-valve type, 2,250 horse-power ca¬ 
pacity, can be brought up to speed from a standstill in five minutes if 
it is hot all over. This five minutes is to be compared with the seventy 
seconds required for the similar turbine operation. 

“A reciprocating engine, which is turning over slowly with the 
throttle-valve just off its seat or with by-pass open, and having all 
its oil-cups open and regulated, can be brought up to speed—say, 
seventy-five turns—in two and one-half minutes. This can be com¬ 
pared with the thirty seconds necessary for bringing the turbine up 



THE STEAM-TURBINE 


347 


under the same conditions; that is, about one-fifth the time necessary 
for bringing tip the engine. 

“If the engine is cold all over and has all its oil-cups shut tight 
and all its auxiliaries quiet, fifteen minutes is called a rapid start. 
Starts have been made under such conditions in twelve minutes. 
When we start a cold turbine, we open up the valve and let her turn, 
and in two minutes we are ready to bring her up to speed, and she 
will be at speed in two and one-lialf minutes, dividing the engine’s 
time by more than four.” 


The points of practice here suggested from an engineer’s experience 
in operating large steam-plants are well worthy of study and remem¬ 
brance by all engineers, and their appeal is directly urged upon the 
student, who may profit by them in his initial trials. Their neglect 
has caused many wrecks in expensive installations of steam-power, re¬ 
sulting not only in the expense of repairs, but often the delay is the 
most expensive item in the wreckage cost. 


CHAPTER XX 


MECHANICAL REFRIGERATION-ENGINEERING 

The principal difficulties encountered in becoming a competent 
engineer in charge of refrigerating-machinery do not include a thor¬ 
ough comprehension of the fundamental principles, but are found in 
the arrangement of the piping and valves of which the greater part 
of the system consists. It requires considerable practice to learn 
what to do and when to do it, and to be able to note the little changes 
and minor adjustments which affect the economical production of low 
temperatures. 

Refrigeration in principle can be learned without special effort, 
but the proper manipulation of the various valves and knowing 
what results should be obtained at the various points in the system 
require the assistance of an experienced person. Even practice may 
be obtained without special instruction; but experimenting with 
ammonia is usually found to be very different from experimenting 
with steam or water under like pressures, and it is liable to lead to 
accidents and unnecessary expense. 

The more noticeable effect upon the general demeanor of the suc¬ 
cessful refrigerating-engineer, due to a thorough knowledge of the 
peculiarities and requirements of ammonia, is that of making him 
careful and thorough in every detail of his work. Makeshifts in a 
refrigerating-plant cannot be tolerated. Whatever is done must be 
done thoroughly, in order to avoid increasing annoyance, if not un¬ 
necessary expense and actual danger. An engineer accustomed to 
operating a refrigerating-plant will usually be found a careful person 
in any plant. Beside this he will have broadened his knowledge of 
the compression and expansion of gases and of the generation and 
removal of heat and its effect upon various substances and liquids; 
in fact, he will have taken another step forward toward the mastery 
of the various sciences underlying and connected with steam-engin¬ 
eering. 

34S 




349 


MECHANICAL REFRIGERATION-ENGINEERING 

Engineers can scarcely expect to escape refrigerating-machinery, 
no matter where they go. Small dairies and cheese-factories located 
in farming districts, abattoirs on country roads; in fact, any estab¬ 
lishment large enough to warrant the use of a steam-boiler and in 
which low temperature is required for the preservation of the product 
is likely to, and oftentimes does, contain a refrigerating-apparatus 
of one kind or another. 

Thus mechanical refrigeration has become one of the branches 
of steam-engineering—one that has made a considerable demand 
upon the ingenuity, and resourcefulness of the engineer, and has 
become so important a part of the engineer s education that the time 
is not far distant when the steam-engineer will not be considered 
thoroughly competent without a working knowledge of both the 
compression and the absorption system. 

ANHYDROUS AMMONIA 

Ammonia is a gas composed of 82.35 per cent, of nitrogen and 
17.65 per cent, of hydrogen. It is very much lighter than air, its 
specific gravity being 0.589. It is characterized by a pungent, suffo¬ 
cating odor, and by its high solubility in water, one volume of water 
at 32° F. absorbing 1,050 volumes of gas. This solution of the gas in 
water is what is commonly known as aqua ammonia, and it rather 
confuses the situation, because the water-solution of gas is used in 
the absorption system of refrigeration, while the ammonia used in 
the direct expansion and compression system is an entirely different 
product. The product known as anhydrous ammonia is the gas 
itself liquefied by intense pressure. It has absolutely no water con¬ 
tent, and is strictly analogous to liquid air, but liquid air consists of 
two distinct substances, each one a gas liquefied by intense pressure— 
that is to say, the nitrogen and hydrogen in anhydrous ammonia 
are chemically combined to a single substance, while in liquid 
air the oxygen and nitrogen composing the air are not chemically 
combined. 

Anhydrous ammonia boils at a fixed temperature of 28.6° F. 
below zero. One pound of liquid ammonia at 32° F. would occupy 
21 cubic feet when evaporated to a gas at atmospheric pressure, and 
the vaporization of a pound requires 555.5 British thermal units. It 


350 


MECHANICAL REFRIGERATION-ENGINEERING 


is a colorless and very mobile liquid. It has a specific gravity of 
0.613 compared with water at 60° F. A cubic foot of anhydrous 
ammonia weighs 42.1 pounds. 

The usual method of detecting impurities is by evaporation of a 
measured amount of the substance. The residue remains in the 
bottom of the tube, and can be either weighed or measured. Not 
many years ago it was quite common to have ammonia containing 
as high as 15 per cent, of impurities; to-day commercial ammonia 
rarely contains 0.5 per cent, of impurities. It is stated that Armour’s 
anhydrous ammonia does not exceed 0.1 per cent, of impurities, and 
usually but the merest trace. Impurities amounting to 2 per cent, 
are detrimental, as they affect the refrigerating value of anhydrous 
ammonia. Impurities of 0.1 per cent, or less can be disregarded. It 
is true these impurities accumulate in the system, but when the 
amount is but 0.1 per cent., this has little effect on the action of 
ammonia in the refrigerating-plant, and its accumulation is very 
slow. 

Without going into a discussion of the availability of the several 
different gases for refrigerating purposes, it may be said that ammonia 
combines the required characteristics and therefore is found to be 
most suitable; for when we consider the pressures at which other 
gases can be made to liquefy when at ordinary temperatures and the 
amount of cold water that otherwise would be required, together 
with the important item of safety or the absence of dangerous qual¬ 
ities, it is easily understood why ammonia is best adapted to the pur¬ 
pose. Therefore we will consider the ammonia compression system 
of refrigeration from the standpoint of the engineer in charge of the 
machinery and whose success in handling it will be directly in pro¬ 
portion to his knowledge of the principles involved, together with 
the details of the machinery and the care bestowed upon it. 

When ammonia is received ready for the system it is in the liquid 
state enclosed in steel drums, which are only partly filled, leaving 
space enough for expansion so as to prevent an explosion of the drums. 
Ammonia-drums have exploded, but always under conditions of 
overheating, for in general, with proper care, there is no danger. 
When liquid ammonia evaporates into gas under a lower pressure, 
heat must be added to supply the latent heat of the gas corresponding 
t° that pressure and temperature. The latent heat of the gas and 


MECHANICAL REFRIGERATION-ENGINEERING 


351 


many other points regarding pressures and temperatures may be found 
from the following table, which gives the more important properties 
of ammonia. 


Table XL. —Properties of Ammonia. 


Gauge-pres¬ 
sure, pounds 
per square 
inch. 

Absolute pres¬ 
sure, pounds 
per square 
inch. 

Temperature, 
degrees F. 

Absolute tem¬ 
perature, 
degrees F. 

Latent heat of 

evaporation in 

thermal units. 

Volume of 1 

pound vapor 

in cubic feet. 

Weight of 1 

cubic foot of 

vapor in 

pounds. 

Volume of 1 

pound of liquid 

in cubic feet. 

Weight of 1 

cubic foot of 

liquid in 

pounds. 

- 4.01 

10.69 

-40 

420.66 

579.97 

24.38 

.0410 

.0234 

42.589 

- 2.39 

12.31 

-35 

425.66 

576.68 

21.32 

.0469 

.0236 

42.337 

- 0.57 

14.13 

-30 

430.66 

573.69 

18.69 

.0535 

.0237 

42.123 

1.47 

16.17 

-25 

435.66 

570.68 

16.44 

.0608 

.0238 

41.858 

3.75 

18.45 

-20 

440.66 

567.67 

14.51 

.0690 

.0240 

41.615 

6.29 

20.99 

-15 

445.66 

549.35 

7.23 

. 1383 

.0243 

41.375 

9.16 

23.80 

-16 

450.66 

546.26 

9.49 

.1541 

.0250 

41.135 

12.22 

26.92 

- 5 

455.66 

543.15 

5.84 

.1711 

.0252 

40.895 

15.67 

30.37 

0 

460.66 

540.03 

5.27 

.1897 

.0253 

40.655 

19.46 

34.16 

5 

465.66 

536.91 

4.76 

.2099 

.0255 

40.415 

23.64 

38.34 

10 

470.66 

549.35 

7.23 

.1373 

.0249 

40.160 

28.24 

42.94 

15 

475.66 

546.26 

6.49 

. 1541 

.0250 

39.920 

33.25 

47.95 

20 

480.66 

543.15 

5.84 

.1711 

.0252 

39.682 

38.73 

53.43 

25 

485.66 

540.03 

5.27 

.1897 

.0253 

39.432 

44.72 

59.42 

30 

490.66 

536.91 

4.76 

.2099 

.0255 

39.200 

51.22 

65.92 

35 

495.66 

533.78 

4.31 

.2318 

.0256 

38.950 

58.29 

72.99 

40 

500.66 

530.63 

3.91 

.2554 

.0258 

38.700 

65.96 

80.66 

45 

505.66 

527.47 

3.56 

.2809 

.0260 

38.480 

74.26 

88.96 

50 

510.66 

524.30 

3.24 

.3084 

.0261 

38.230 

83.22 

97.92 

55 

515.66 

521.12 

2.96 

.3380 

.0263 

37.980 

92.89 

107.59 

60 

520.66 

517.93 

2.70 

.3697 

.0265 

37.736 

163.37 

118.03 

65 

525.66 

514.73 

2.48 

.4039 

.0266 

37.481 

114.49 

129.19 

70 

530.66 

511.52 

2.27 

.4401 

.0268 

37.230 

126.52 

141.22 

75 

535.66 

508.29 

2.09 

.4791 

.0270 

36.995 

139.40 

154.10 

80 

540.66 

505.05 

1.92 

.5205 

.0272 

36.751 

153.18 

167.88 

85 

545.66 

501.81 

1.77 

.5649 

.0273 

36.509 

167.92 

182.62 

90 

550.66 

498.55 

1.64 

.6120 

.0275 

' 36.258 

183.65 

198.35 

95 

555.66 

495.29 

1.51 

.6022 

.0277 

36.023 

200.42 

215.12 

100 

560.66 

492.01 

1.39 

.7153 

.0279 

35.778 

218.28 

232.98 

105 

565.66 

488.72 

1.289 

.7757 

.0281 


237.27 

251.97 

110 

570.66 

485.62 

1.203 

.8312 

.0283 


259.70 

272.14 

115 

575.66 

482.41 

1.121 

.8912 

.0285 


275.79 

293.49 

120 

580.66 

478.79 

1.061 

.9608 

.0287 


301.46 

316.16 

125 

585.66 

475.40 

.9699 

1.0310 

.0289 


325.72 

310.42 

130 

590.66 

472.11 

,9051 

1.1048 

-.0291 



































































































352 


MECHANICAL REFRIGERATION-ENGINEERING 


The ammonia-compressor is a compression-pump, and may be 
considered as such in every sense of the word, but it must be a better 
pump than those which are more common in the steam-plant. The 
object of this pump is to take ammonia gas from the refrigerating 
portion of the system, and compress it to a considerable pressure and 
discharge the compressed gas into the condenser. The latter is a 
series of pipes over which water is kept flowing for cooling, and, finally, 
for the liquefaction of the gas. The ammonia, on being liquefied 
in the condenser, passes on to the ammonia-receiver, which is a vessel 
of any convenient size and shape adapted to hold a suitable quantity 
of the liquid and from which a considerable quantity may be with¬ 
drawn continuously and evaporated in the refrigerating-pipes. In the 
latter, sufficient heat is absorbed to supply the latent heat required 
by the gas, after which the gas returns to the compressor. 

With the foregoing brief description of the essentials of the system, 
the engineer may proceed to start the compressor for continuous 
work. The compressor may be driven by a steam-engine or electric 
motor, and in some cases water-power is used for this purpose. When 
shutting down their engines or stopping the compressor for any 
reason, some engineers leave the discharge- and suction-valves in the 
ammonia system open, as they were during the time the machine 
was running, while others often close the suction- and discharge- 
valves and sometimes forget to open them before trying to start. 
Do not make this mistake, for many accidents have happened because 
the discharge-valve was closed when the compressor was started. 

There is not as much danger in leaving the suction-valve closed, 
for the worst that could happen would be to create a high vacuum on 
the suction side. If the discharge-valve happens to be closed, each 
stroke of the compressor will add to the pressure in the discharge- 
pipe, which will soon run up to a dangerous point. The careful 
engineer will keep his eye on the pressure-gauge while starting the 
compressor and until he is assured that the compressor is running 
at the proper speed and that there is a free escape for the ammonia. 
Usually there are no cylinder-cocks to be opened previous to the 
starting ol the compressor and none to be closed, except on the steam 
end. There is little chance therefore for the engineer to make a mis¬ 
take, provided the pressure-gauge shows that the pressure is within 
the proper limits. 


353 


MECHANICAL REFRIGERATION-ENGINEERING 


Forward or compressor pressure required is determined in nearly 
all cases by the temperature and amount of the condensing water. 
Further information on this point may be obtained by examining the 
temperatures and consequent pressures as given in the table, where it 
will be found that ammonia under a pressure of 200 pounds to the 
square inch has a temperature of about 100° F., while the cooling 
water may have a temperature of only 50°. The boiling-point of 
ammonia under 200 pounds pressure with a temperature of 100°, 
shows that the temperature of the compressed gas must be reduced 
below 100° in order to be able to liquefy it. 

There is a difference of a few degrees between the temperature of the 
gas or liquid inside the pipe and the temperature that will be obtained 
on the outside—that is, where the ammonia-pipes in the condenser 
are clean and free from scale, mud, and slime. The difference of 
temperature inside and outside the pipes will range from 5 to 8° 
under usual working conditions. With unfavorable conditions the 
difference in temperature may be almost any amount. A difference 
of temperature will also be found in the refrigerating-pipes, and this 
will be found to be about the same number of degrees under the 
same conditions. 

With a gas-pressure in the condenser of 200 pounds and with 
water at 50° flowing over the condenser-pipes, the best conditions 
will be obtained when the temperature of the water leaving the con¬ 
denser is within a few degrees of the temperature of the ammonia 
inside the pipes. The temperature due to the pressure of the am¬ 
monia gas in the condenser is always a few degrees higher than that 
due to the boiling-point of liquid ammonia under the pressure carried. 
This difference of temperature is due to the superheating of the 
ammonia when compressed in the compressor, which will vary ac¬ 
cording to the conditions of operation and the kind of compressor used. 

Suction-pressure on the system is nearly always a few pounds 
above that of the atmosphere, although it is sometimes found necessary 
to reduce this pressure below that of the atmosphere for special 
kinds of work. For economical results the less difference between 
the condenser- .and suction-pressures the less power will be required 
to operate the system. For a given amount of refrigeration the 
suction-pressure usually is regulated by the lowest temperature 
required in all parts of the system, provided the proper amount of 



354 


MECHANICAL REFRIGERATION-ENGINEERING 


piping is employed. The engineer must make sufficient allowance 
for the loss of temperature by transmission through the pipes, which, 
as previously mentioned, may amount to from 5 to 8°, but some¬ 
times may reach a much higher figure. Reference to the table of 
pressures and corresponding temperatures will indicate the proper 
suction-pressure for the lowest temperature it may be required to 
reach. 

When considering the principles of operation of a mechanical 
refrigerating-plant, we shall see that the effects produced are all due 
to a simple exchange of heat, for when we compress the gas we squeeze 
out, so to speak, a certain portion of the latent heat, and the gas 
being under pressure, its latent heat is less than when under a lower 
pressure. The latent heat taken up by the water requires a much 



Fig. 328.—Diagram illustrating the principles of refrigeration by ammonia. 

larger quantity of water for condensing purposes than that due merely 
to the difference between the temperature of the compressed gas and 
that of the liquid ammonia under this pressure. 

Superheating of the gas is due to the latent heat set free by the 
greater density of the compressed gas, and it is the removal of this 
latent heat which gives the liquid greater capacity for absorbing 
heat, and as heat-absorption is the object to be attained the ammonia 
should not be fed to the refrigerating portion any faster than it can 
absorb heat. Furthermore, when it reenters the compressor it should 
be all gas, except in cases where a small amount of liquid is permitted 
to enter the compressor for purposes which will be explained later. 
































































































MECHANICAL REFRIGERATION-ENGINEERING 355 

One way in which the proper pressure on the suction side may 
be determined is by frost covering the suction-pipes. As long as 
there is frost on the pipes it shows that there is still unevaporated 
ammonia in the pipe. Some engineers do not appear to understand 
clearly whether it is the ammonia gas or the liquid ammonia that 
absorbs heat. A simple test will determine this point in a way that 
will render clear to the average person just what takes place in the 
pipe when partly filled with ammonia. It will also demonstrate the 
temperature produced on the outside of the pipe. Ammonia gas has 
little effect in absorbing heat, because the gas is already supplied 
with nearly the full quantity of latent heat required to keep it in the 
gaseous condition. This point can be made clear by taking a test- 
flask or a common tumbler partly filled with liquid ammonia and 
exposing it to the atmosphere. As heat is supplied from the flask 
and the surrounding atmosphere, the ammonia will begin to boil to a 
noticeable degree, which, however, will continue for a moment only, 
for the contents of the flask soon become cooled to such an extent 
that a coating of frost is produced on the surface by the condensation 
of moisture from the atmosphere. 

Frost thus produced will increase in thickness until a layer is ob¬ 
tained through which heat can pass less readily; then the boiling of 
the ammonia will be greatly reduced, and only small bubbles of gas 
will be seen rising through the liquid and given off at the surface. 
The level of the liquid ammonia in the flask is marked by the frost- 
line on the outside, no frost whatever appearing at a greater height 
than the level, except perhaps for J inch or so where the warmer gas 
is in contact with the glass. Air on the outside and the gaseous 
ammonia on the inside cause the frost to melt and form a thin ring of 
ice or a mixture of ice and water at the line where gas and liquid meet. 
This experiment should prove conclusively that it is the liquid am¬ 
monia that does the work of absorbing heat under the conditions 
noted, in which case ammonia gas under pressure, the conditions may 
be considered as being the same as in the glass, for the latent heat 
in the ammonia gas at the suction-pressure has been fully supplied, 
and the gas has no further capacity for absorbing heat. Therefore 
the liquid ammonia only is available for that purpose. Thus we can 
readily understand that ammonia passing through the pipes in the 
refrigerating system remains partly in the liquid state as long as there 


35G 


MECHANICAL REFRIGERATION-ENGINEERING 


is frost on the pipes, and that the point where the liquid ceases to 
exist as such is marked by the absence of frost. 

The amount of liquid ammonia to be supplied to the refrigerating 
system is thus determined by the coating of frost on the pipes, since 
the presence of frost is a sure indication that there is some liquid 



ammonia in the pipe at that point, while the absence of frost indicates 
that the temperature of the pipes cannot be below the freezing-point. 
In some systems frost is carried back to the compressor; in other 
systems frosty pipes are only carried inside the cooling-rooms. It 
may be said, regarding the presence of frost on the pipes and the 
absence of it, that so long as we are dealing with ammonia gas we 
have only the specific heat of the gas to aid us in obtaining the cooling 




















































































































































































































357 


MECHANICAL REFRIGERATION-ENGINEERING 


effect, but in the transformation from the liquid to the gaseous state 
we have not only the specific heat of the liquid but the latent heat of 
the ammonia. The specific heat would not pay for the work required 
in compression, for the latent heat is what is most important, and it 
may be considered that it is all that is available in evaporation of 
liquid ammonia. 

It is well known by all engineers that the compression of air or 
gas develops a large amount of heat, while the expansion of a gas 
will absorb heat, thus producing a lower temperature of the surround¬ 
ings. It is also well known that the evaporation of a liquid, which 
is thus transformed into a gas, will absorb heat, and that the amount of 
heat thus absorbed will be equivalent to the latent heat of the gas 
at the pressure under which it is generated. 

Fig. 329 illustrates this principle for operating a compressor. A 
simple non-condensing automatic engine drives a crank-shaft in the 
usual way, but a vertical connecting-rod is driven by the same crank- 
pin, and this gives motion to a vertical compressor, as shown. A 
heavy balance-wheel on the same shaft provides steady motion for the 
moving parts by absorbing power during the first part of each stroke 
and giving it out during the latter part. The illustration shows a 


Fig. 330.—Three stages of refrigeration. 



Compression 

Refrigerating 

Apparatus 


Water Supply 
Condenser C 


VALVE, 


duplex compressor. One cylinder is located just over the engine- 
crank, while another crank and cylinder are placed on the other end 

of the shaft. 

In Fig. 330 are illustrated the three principal phases or stages in 




































































































































WATER SUPPLY TANK 



Fig. 331.—Complete ice-making plant of the Frick Company illustrating the various stages in the operation of refrigeration. 





























































































































































































































































































































































MECHANICAL REFRIGERATION-ENGINEERING 


359 


the operation of refrigeration by the ammonia compression system, 
although in a complete plant there are many adjuncts for special 
service, such as oil-separators, receiving-tanks, filters, and brine-agi¬ 
tators, which are shown in the full-page cut, Fig. 331. 

In the simple round of ammonia-circulation, it starts from the 
compressor under a high pressure and temperature, passing to a 
cooling-coil, which is the condenser, where, by means of a cold-water 
sprinkler, the gas is cooled to 45° or 50° F. At that temperature, 
under the high pressure the gas is condensed 
to its liquid state and passes to a storage-tank, 
or may be throttled by a valve to maintain a 
constant pressure on the liquid, and, by allowing 
of control in its issue to the refrigerating-coil, 
and by its reevaporation therein under a low 
pressure, to absorb the heat of the brine or air 
in a cold chamber that is required for vaporiz¬ 
ing the liquid ammonia within the coils. 

Fig. 332 illustrates the De La Vergne stand¬ 
ard double-acting vertical compressor, the 
operation of which may be explained as follows: 

Suppose that the piston is ascending with a 
charge of gas above it. As the space holding 
this gas becomes less its pressure rises until it 
is high enough to overcome that carried on the 
discharge-pipe. There are two discharge-valves 
in the upper part of this machine, a full view 
of one and a section of the other being shown. 

These rise and let the compressed gas out 
through the right-hand passage to the conden¬ 
ser. At the same time gas under light pressure is drawn in through 
the lower suction-valve, at the left hand, until the space below 
the piston is filled with it. As the downward stroke is made 
this gas is compressed until the pressure is high enough to force 
it out, through the two lower discharge-valves at the right, to the 

condenser. 

There is a hollow space in the piston, covered by two valves 
opening upward. When the piston has nearly reached the end of 
its downward stroke and the lower valve is closed by the piston. 



Fig. 332 .— De La Vergne 
vertical ammonia- 
cyli rider. 
































































360 MECHANICAL REFRIGERATION-ENGINEERING 

the pressure is sufficient to raise the valves and discharge the gas. 
through the higher one of the right-hand discharge-valves, to the 

condenser. 

Fig. 333 shows the sectional details of the single-acting com¬ 
pressor of the Frick Company. r lhe gas at suction-pressure enters 
below the piston from the right-hand valve, passing through a light 
spring-balanced valve in the piston, is compressed above the piston, 
and is discharged, through the lifting of the large spring-held valve, 
at the top of the piston, and to the condenser. 

The principal feature in this design is the safety-head or discharge- 
valve, which allows the piston to touch it at each stroke, thus elimi¬ 
nating all clearance and adding its 
effect to the efficiency of the com¬ 
pressor. The apparent striking of 
the discharge-valve at the moment 
of the passage of the crank-centre, 
or even slightly before it, can do 
no damage, as the valve is lifted at 
that moment and falls gently upon 
the piston-head during the last of 
the discharge. 

Fig. 334 illustrates a section 
of the De La Yergne horizontal 
double-acting ammonia-compressor 
cylinder. It has some features of 
safety not covered in many gas- or 
air-compressors. This cylinder has 
as small clearance as possible, in 
view of which it will be seen that 
the valves must be as near the 
piston as practical, in order to make the clearance small and produce 
an economical machine. The suction-valves are above the cylinder 
in this case and the discharge-valves below it; consequently if any 
liquid finds its way into the cylinder it is well drained out. None of 
the valves can drop into the cylinder in case the springs break, which 
is an important consideration. 

In all double-acting machines the piston-rod stuffing-box is sub¬ 
jected to the full compression-pressure, which may be over 200 pounds, 



Fig. 333.—Frick Company ainnionia- 
cy Under. 


























































MECHANICAL REFRIGERATION-ENGINEERING 


361 


and as this gas is of a penetrating nature, especially when under such 
high pressure, it is sometimes difficult to keep a stuffing-box tight 



Fig. 334.—De La Vergne horizontal ammonia-cylinder. 


without excessive friction. This is accomplished here by the use of 
two sets of packing-rings, and between them there is a device for 
oiling the rod, which is plainly shown. 

SURFACE- AND DOUBLE-PIPE CONDENSERS 

The Linde surface-condensers (a portion of which is shown in Fig. 
335) are built in such a way that the flanges at each end of the straight 
pipes, when screwed together, form a hollow column, which, b} 
means of special flanges, is divided into different compaitments. Tlic 
warm ammonia gas, when discharged into the top of one of the col¬ 
umns, is divided, so as to reduce the velocity, and then passed tliiough 
three pipes. At the other end the three pipes join, and the gas, afte i 
being mixed, is again divided into six or more pipes, so as to still 
further reduce the velocity and give it time to become thoroughly 
cooled. This action is repeated until the ammonia is delivered at the 
bottom of the condenser in liquid form. By reducing the velocity 
the friction also is reduced, and condensation is effected m a shorter 
time. The pressure also is considerably reduced, which m some 
cases amounts to 25 pounds. 

From the lower part of the condenser the liquid ammonia is drawn 







































































































362 


MECHANICAL REFRIGERATION-ENGINEERING 



Fig. 335.—Surface-condenser. 


off and passed through a sepa¬ 
rate upper pipe, where it is 
brought in contact with the cold¬ 
est water and cooled down as 
near as possible to the tempera¬ 
ture of the water. 

The construction of the 
double-pipe condenser, Fig. 336, 
is such that one pipe is placed 
within the other, which pipes, 
at each end, are connected by 
special bends, so as to make two 
separate zigzag sections of inner 
and outer pipes. 

Ammonia gas enters at the 
top and is forced downward 
through the large outer pipe, 
while the water enters at the 


bottom and is forced upward 
through the smaller inner pipe. 
As the water does not come in 
contact with the atmosphere, 
after having cooled the gas it 
can be used for other purposes. 
As no water runs over the out¬ 
side pipes, no tank is required 
to collect the condensing water, 
and therefore the condenser can 
be placed in any room, pro¬ 
vided the temperature of the 
room is not too high. On ac¬ 
count of placing one pipe with¬ 
in the other the space allowed 
for the ammonia gas is small, 
and consequently the amount 
of gas surrounding the water- 
pipes is also small, so that heat 
is quickly extracted. This is an 





















































































































































































































































































































363 


MECHANICAL REFRIGERATION-ENGINEERING 


advantage, since the quicker ammonia gas is cooled and liquefied, the 
lower will be the pressure, and less power is required to drive the com¬ 
pressor. As the coldest water enters at the lower end of the coil- 
section, where the liquid ammonia collects, a thin layer of liquid 
ammonia is quickly reduced to the temperature of the coldest water. 
The surface-condenser has the advantage that the pipes are always 
open for inspection, and can be cleaned and painted when necessary, 
and always kept in good condition. With a double-pipe condenser, 
where the water-pipe is inside, they cannot be so readily examined, but 
special provisions are made for cleaning the pipes. In certain cases 
where the required quantity of cooling water is limited, or where water 
is metered and must be paid for, a condenser of special design is built 
with the object of saving water. With these condensers, which are 
called evaporative condensers, the quantity of cooling water is reduced 
to one-tenth the quantity required for ordinary condensers. The 
latter condensers, on account of their special construction, are some¬ 
what more expensive in first cost, but where water is scarce or has 
to be paid for they soon pay for themselves. 


THE DIAGRAM OF AMMONIA- COMPRESSION 

y 

The specific heat of anhydrous ammonia is about the same as that 
of water, or, more exactly, 1.096 at 0° F., and decreases with the 
rise in temperature at the rate of .0012 per degree F. 

The latent heat of vaporization at —40° F. is 579.6 thermal units 
per pound, sustaining a pressure of 10.7 pounds per square inch. Its 
latent heat decreases gradually with increasing temperature and 
pressure, and at 100° F. is 491.5 thermal units per pound, and sustain¬ 
ing a pressure of 215 pounds per square inch. 

The compression of its vapor follows the adiabatic law of gases 
and vapors, subject to the influence of the walls of the cylinder in 
absorbing the heat of compression. 

Fig. 337 shows a diagram of the compression-lines for ammonia 
vapor between the return-pressure of 20 pounds and discharge- 
pressure of 150 pounds per square inch. The adiabatic line is repre¬ 
sented by the logarithmic exponent of the P V equation, which is 
1 . 297 ^ or i.3 ag generally expressed; the equation in which the P V 1,3 = 
Pi Vi 1,3 represents the integration of the curve. 


364 


MECHANICAL REFRIGERATION-ENGINEERING 


It, will be seen that the absorption of heat by the cylinder-walls 
drops the line of compression below the adiabatic line, and thus 



Fig. 337. —Diagram of ammonia-compression. 


contributes to the efficiency of the compressor, and also shows the 
volume of delivery between the observed temperatures. 

POINTERS ON THE OPERATION OF AMMONIA 
COMPRESSION SYSTEMS 

It is not the intention of the author to go very deeply into the 
theory of mechanical refrigeration, as the practical end of the business 
is where trouble is generally found; but it is absolutely necessary 
for the engineer to have the right foundation on which to base his 
practice, and to assist in this a few definitions and rules will be given. 

Mechanical refrigeration is brought about by. an exchange of 
heat between two bodies; and it is well to remember that whether heat 
is sensible or latent it is never destroyed, but simply removed or ab¬ 
sorbed by another body whose temperature is lower than that of the 
body from which heat is taken. Heat that manifests itself by means 
of the sense of feeling or by the aid of a thermometer is called sensible 
heat. In changing a solid into a liquid, or a liquid into a gas, a certain 
amount of heat is required to effect the transformation, and this is 
called the latent heat. 

The process of refrigeration by the compression system is divided 








365 


MECHANICAL 


REFRIGERATION-ENGINEERING 


into three stages, compression, condensation, and expansion. The 
ammonia gas is first drawn into the compressor and compressed to 
approximately 150 pounds per square inch. During compression 
the latent heat of the gas, which in this case is the amount of heat 
absorbed in its transformation from a liquid into a gas, is given up in 
form of active or sensible heat. Some compressors have a water- 
jacket cylinder to prevent this heat from doing damage by destroying 
lubrication, but as the jacket has only a local effect, it is sometimes 
found necessary to inject oil in large quantities, and this generally 
causes trouble by passing the oil-trap in the form of a vapor and coating 
the condensing system. Some compressors are so arranged that a 
small portion of the liquid ammonia is carried back to the machine 
and converted into gas during the compression period, and that the 
latent heat thus absorbed assists in keeping the temperature of com-- 
pression down to a point where water-jackets are not necessary. If 
the temperature can be kept down to about 120 to 130° F. no trouble 
will be experienced from that source. 

When gas at 150 pounds pressure is forced into the condenser, 
the cooling water running over the pipes absorbs the active or sensible 
heat developed during compression, thus removing the heat which 
was necessary to keep the ammonia in a gaseous state, and again 
transforming it into a liquid at a temperature approximating that of 
the condensing water, but at the pressure existing in the condenser. 
The liquid ammonia is admitted to the expansion-coils through a 
regulating- or expansion-valve in such quantities as are necessary 
for the work on hand. In these coils, owing to the lower pressure 
maintained, the liquid ammonia again expands into a gas, and during 
this transformation absorbs practically the same amount of heat 
from surrounding objects that it gave up to the cold water in the 
condenser. 

\ 

The economical operation of a plant of this kind requires two 
things, viz., pure ammonia, as the boiling-point of ammonia varies 
directly in relation to the purity, and keeping the system in such a 
condition that ammonia will not be lost as a result of leaks. This 
trouble is one frequently met with. The compressor runs smoothly 
and everything seems to be as it should, but perhaps the proper 
results are not being attained in the pipe-lines. Perhaps direct- 
expansion piping does not frost up as it should and brine tempera- 


366 


MECHANICAL REFRIGERATION-ENGINEERING 


tures are too long falling. The usual trouble is the lack of liquid 
ammonia in the system, or some obstruction at the expansion-valve. 
If there is sufficient ammonia the gas will be running heavy enough 
to make a very distinct clicking at the valves in the compressor, 
while with a lighter gas caused by a lack of liquid these valves will 
be almost if not entirely noiseless. If the trouble is at the expansion- 
valve it is generally easy to detect it by opening and closing the 
valve several turns and listening to the passage of the ammonia, 
for if the valve is at fault the sound will remain the same at all posi¬ 
tions. 

Having a machine too small for the work will also make a poor 
showing at the expansion-coils, but if there is plenty of ammonia in 
the system, trouble from this cause will also be accompanied by a 
high back pressure, as the ammonia expands to a gas faster than the 
machine can take care of the gas, and in consequence the back pressure 
will build up until the extra pressure in the expansion-coils is suffi¬ 
cient to retard the inflow of liquid ammonia and the consequent 
evaporation. If the expansion-valve is found to be passing gas, or 
if the temperature of the pipe between the liquid-receiver and the 
expansion-valve is found to be much below that of the condensing 
water, the engineer will be safe in assuming that the supply of am¬ 
monia in the system is too small. The condenser-coils should be 
kept free from permanent gases by the use of a gas- or purge-valve 
located at the top of the coils, and they should be kept as clean as 
possible at all times so that the entire benefit of the water may be 
derived. 

In looking for leaks in the system, they may be quite easily located 
by making long sulphur matches out of pine splinters by dipping 
them in melted sulphur, and, after lighting, holding one of them close 
to and around the point thought to be leaking. If the leak is there, 
the sulphur fumes and the ammonia fumes will combine and form a 
dense white vapor. This is also a good point to remember where direct 
expansion is used in the cold-storage rooms, as in case of a break or 
a severe leak the ammonia gas can be neutralized by this method, 
merely placing a pan of burning sulphur inside the room. In this way 
work can be started much sooner than would be possible, unless there 
is some good means of ventilation, which as a general thing is not 
provided. A good-sized stream of water from a hose directed on a 


MECHANICAL REFRIGERATION-ENGINEERING 


367 


seiious break in an ammonia-pipe will sometimes enable the engineer 
to get to the stop-valve and close it before the whole charge of am¬ 


monia is lost. A common source of small leaks is the piston-rod 
stuffing-box; and the engineer should use great care in packing this 


box, because a leak at this point is both costly and disagreeable. 
The packing should fit the stuffing-box snugly, and be cut to lengths 
so that the ends will meet but not overlap. This packing should be 
tight enough to require tapping into place with a wooden packing- 
stick and small hammer. 

Coils of ammonia-condensers usually are vertical pipes connected 
with return-bends. Should a leak develop near the centre of the 
coil, the quicker remedy is to cut the nearest return-bend with a 
hack-saw and remove the two pieces, after which the leaky pipe 
may be attended to properly and the joint made by using a return- 
bend made in two or three parts and clamped together with bolts. 
While on the subject of pipe-joints for holding ammonia, several kinds 
that give good service may be mentioned. A joint may be made by 
tinning the fitting and the end of the pipe and heating them hot enough 
to make a sweat-joint when screwed together. If an annular space is 
made in the fitting about two threads deep, and if after making the 
fitting up tight, this space is filled with solder and wiped off, it makes 
an excellent joint, but it is slow, costly work and requires careful hand¬ 
ling. A common way is to clean the threads with naphtha or gasolene, 
and then paint them with a pigment made of glycerine and litharge. 
This will harden in a short time, and if carefully put up will give 
excellent results. 

In making pure crystal can ice perhaps the greatest difficulty the 
engineer will encounter will be to keep it clear and free from cores. 
Absolute cleanliness is the greatest help toward attaining this end. 
The red core is caused by iron oxide from the steam-condenser coils 
getting past the filters, which is something that can be prevented 
if proper care is taken. The boilers should be kept clean along with 
the rest of the plant, as they are the source of the distilled water, 
and some little water is apt to be carried over with the steam. This 
may not be much, but if the boilers are dirty it will often show in the 
ice. A leak in the steam-condenser will often bring in enough foreign 
matter to cause discoloration in the ice. 

If the temperatures in a cold-storage room are not low enough and 


368 


MECHANICAL REFRIGERATION-ENGINEERING 


the coils are not frosted to the ends, evidently the first thing to dc 


is to find out why they cannot he made to carry frost throughout their 
entire length. The fact that a direct-expansion pipe accumulates 
frost indicates simply that the vapors and liquid ammonia passing 


through it are at a temperature sufficiently low to congeal the moisture 
of the air which comes in contact with it. So long as there is un¬ 
evaporated liquid ammonia in contact with the vapor, the latter is 
said to be saturated , and the temperatures corresponding to the 
different back pressures can be readily determined by reference to the 


table XL of Properties of Saturated Ammonia. 

If there is liquid ammonia enough at the expansion-valve, frost 
can be carried the full length of any coil and clear back to the machine, 
if desired, at a back pressure of 25 pounds, because the temperature of 
saturated gas at 25 pounds pressure is 11.5° F., which is 20.5° F. 
below the freezing-point of water. That a coil does not frost to the 
end under a back pressure of 25 pounds, indicates that either there is 
an insufficient supply of liquid ammonia at the expansion-valve, or 
that there is an obstruction which prevents a sufficient amount of it 
from passing the expansion-valve. An obstructed expansion-valve is 
indicated by there being little or no change in the sound of the passing 
liquid when the valve is opened several turns. Such obstructions can 
often be removed by the sudden opening and closing of the expansion- 
valve. 

Scarcity of liquid at the expansion-valve can usually be recognized 
by an interrupted hissing sound, the hissing being caused by the 
passage of gas and the interruption by that of the liquid, maybe due 
to one of two things, viz., an insufficient charge of ammonia or too 
small a machine. If there is a sufficiently heavy charge of ammonia 
in the system and the machine is much too small, there will be no 
whistling sound heard at the expansion-valve, but the machine not 
being able to carry away the vapors of ammonia as fast as they are 
formed, the back pressure will rise higher until the extra pressure 
serves to retard the evaporation to such an extent that the machine 
cannot take care of it. It must also be remembered that as the back 
pressure rises the number of pounds of ammonia handled by the 
machine at a given pressure increases, because of the fact that the 
weight of a cubic foot of gas increases directly with the absolute 
pressure. 


MECHANICAL REFRIGERATION-ENGINEERING 


369 


While the size of a machine cannot well be increased, its capacity 
for doing work may sometimes be increased by improving its efficiency. 
Sometimes low efficiency is due to dirt, which acts like an insulating 
material on the condensers and prevents the free radiation of heat; 
sometimes to insufficient or poorly distributed water on the con¬ 
densers, and sometimes to so-called permanent gases within the con¬ 
densation. 

With well-sprinkled coils of ample size 210 pounds head-pressure 
is certainly too high for 59-degree water, and the trouble is liable 
to be due to any of the three causes above mentioned. 

Ammonia as ammonia cannot deteriorate in quality, but at high 
temperatures, and, according to some authorities, more or less at 
moderate temperatures, it does slowly disassociate into its component 
gases, hydrogen and nitrogen. These gases, sometimes called per¬ 
manent gases, because they do not liquefy, accumulate in the con¬ 
denser, and, occupying the space that should be open to the ammonia, 
cut down the cooling-surface and thereby cause an abnormally high 
head-pressure. These gases should be purged from the system 
through a pipe or rubber hose, one end of which is connected to the 
purge-valve on the top of the condenser and the other immersed in 
a pail of water. If a sharp, cracking sound is heard and no bubbles 
rise to the surface of the water when the purge-valve is slowly opened 
it indicates that the gas is soluble in water and is ammonia. If, how¬ 
ever, bubbles rise to the surface of the water the gas is proved to be 
comparatively insoluble and is not ammonia. The gases should be 
allowed to escape through the purge-valve into the water until no 
more insoluble gases appear. The water should be changed every 
few minutes, to keep it from becoming saturated with the ammonia, 
under which condition it will bubble through the water in much the 
same way as the permanent gases do, and may lead to deception 
regarding its true nature. 

There should be enough liquid ammonia in the liquid-receiver at 
all times, so that no gas will pass the expansion-valve. The latter 
condition can be readily recognized by the temperature of the liquid¬ 
line between the receiver and the expansion-valve. It should be re¬ 
membered that the temperature of the liquid ammonia going to the 
expansion-valve should be approximately that of the cooling watei 
leaving the condensers, and that a wide variation in temperatuie 


370 


MECHANICAL REFRIGERATION-ENGINEERING 


either way from that point would indicate an insufficient supply of 
liquid. 

The condenser-coils should be kept clean and well covered with 

water at all times, and they should also be kept purged tree from 

« 

permanent gases. 


CHARGING AND STARTING AN AMMONIA-COMPRESSOR 

As each type of ammonia-compressor has its own individual 
features of construction, each particular machine will require special 
care and adjustment, so that no fixed rules can be laid down to suit 
all cases. There are, however, some general principles which are 
applicable to all types based on the compression system. 

Before charging an empty machine with anhydrous ammonia all 
air must first be carefully expelled. This is done in various ways. One 
method often used is to pump the system full of gaseous ammonia and 
shut the engine down. Allow the water to flow in the condensers 
until all the ammonia in the system is condensed. The liquid am¬ 
monia, being heavier, will naturally gravitate to the bottom of the 
system. A valve can then be opened at the highest part of the sys¬ 
tem, and the pressure of the ammonia will force the air out; the 
presence of ammonia gas will indicate when to shut the valve. The 
system can then be allowed to stand another six or twelve hours, and 
the valve again opened. If there is any air remaining in the system, 
it will be driven out when the valve is again opened. 

Before charging the system it can be thoroughly tested by working 
the compressor and permitting air to enter at the suction through the 
special valves provided for that purpose, and it should be perfectly 
tight at 200 or 250 pounds pressure per square inch, and should be 
able to hold that pressure without loss. While testing the system 
under air-pressure, it should be carefully and thoroughly cleaned of 
all dirt and moisture by blowing out. 

In some cases it is impossible to eject all air from the plant by 
means of the compressor; therefore it is advisable to insert the requisite 
charge of ammonia gradually. Sometimes from 60 to 70 per cent, 
of the full charge is put in, and the air remaining in the system is 
allowed to escape through the purging-cocks with as little loss of gas 
as possible, subsequently inserting an additional quantity of ammonia 


MECHANICAL REFRIGERATION-ENGINEERING 371 

once or twice a day until all the air has been displaced and the complete 
charge has been introduced. 

To charge the machine the drum of anhydrous ammonia is con¬ 
nected through a suitable pipe to the charging-valve. The machine 
should be run at a slow speed when sucking the ammonia from the 
tank, with the discharge- and suet ion-valves wide open. When one 
of the tanks is emptied the charging-valve is closed and another tank 
placed in position, and the process continued until the machine is 
sufficiently charged for work, when the charging-valve can be closed 
and the main expansion-valve opened and regulated. A glass gauge 
upon the liquid-receiver will show when the latter is partially filled, 
and the pressure-gauges, as well as the gradual cooling of the brine 
in the refrigerator and the expansion-pipe being covered with frost, 
will indicate when a sufficient amount to start working has been 
inserted. 

The machine having been started and the regulating-valve opened, 
the temperature of the delivery-pipe should be carefully noted, and 
if it shows a tendency to heat, then the regulating-valve must 
be opened wider, while if it should become cold, the valve must be 
slightly closed, the regulation or adjustment thereof being continued 
until the temperature of the pipe is the same as the cooling water 
which leaves the condenser. If the charge of ammonia is insuffi¬ 
cient, the delivery-pipe will become heated even when the regulating- 
valve is wide open. 

Among the signs which denote the healthy working of the plant, 
beside the fact that it is satisfactorily performing its proper refrigerat¬ 
ing duty, are the vibration of the pointers of the pressure- and vacuum- 
gauges (which clearly mark every stroke of the piston), the Irost on the 
exterior of the ammonia-pipes (the liquid ammonia can be distinctly 
heard passing through the regulating-valve in a continuous stiearn), 
and the difference in temperatures between the condenser and the 
cooling water and the refrigerator and the brine. 


CHAPTER XXI 


THE ELEVATOR AND ITS WORKING 

The modern installation of elevator service lias greatly increased 
the care and responsibility of the engineer, to whom such duties are 
usually assigned; and in view of these duties this chapter will be 
deemed not out of place, for not only the often complex details of the 
elevator but also those of the steam-pump or the electric motor are 
in charge of the engineer. 

The direct-acting steam-motors for elevators are peculiar in their 
design, and require the care and watchfulness of the experienced 
engineer. 


AIR-COMPRESSORS 

The air-compressor—so much in use in operating mining-machines, 
hoists, conveyers, and air-locomotives, and for generating power 
for transmission for a variety of factory and operative purposes—- 
becomes a specialty in the care of the engineer of such plants. 

Of the many types or methods of operating elevators we note the 
following: 

The direct-cable elevator, in which a reversible steam-engine 
winds and unwinds the rope-cable on a drum; the car, which is partly 
balanced by a cable and counterweight, with the stop- and reverse- 
valves operated by a lanyard, over which the car runs. The early 
safety-devices were a form of ratchet-stop (shown in Fig. 338), suc¬ 
ceeded by friction-devices and speed-governors of many patterns. 

Elevators of the type classed as hydraulic, and operated by water- 

pressure from a roof-tank or a pressure-tank fed by a steam-pump, 

are still in use. One of this type is illustrated in Fig. 339, and consists 

of a cylinder of one-half the length of the lift, with a piston and double 

piston-rods for safety. The pressure is downward on the piston, 

for elevating the car. A travelling sheave with the end of the car-cable 

fixed at the top gives the car twice the run of the piston. An auto- 
372 


THE ELEVATOR AND ITS WORKING 


Q —O 

O/O 



Fig. 338. 

stop. 


Elevator- 


matic stop controls the run of the car, and a lanyard-cable controls 
the speed by throttling the circulating-pipe. 

A very compact hydraulic-elevator plant is detailed in Fig. 340, 
with a cylinder-capacity for a gear of 2 to 1 or 4 to 1, as desired. Here 
the pressure-tank is placed over the discharge- 
tank, with the steam-pump alongside. The prin¬ 
ciple of operation is contained in the action 
of the pilot- or transfer-valve, which is itself 
operated by a cable-lanyard passing through the 
car and over a wheel at the top of the shaft and 
over the valve-wheel seen at the top of the valve. 

When the car is at the top of the lift, the 
piston is at the bottom of the cylinder, with the 
valve closed to hold the car. To bring the car 
down, the valve opens the port of the transfer- or circulating-pipe, 
when the weight of the car and load transfers the water from above 
the piston to its under side, the velocity of transfer being regulated 
by the amount of opening of the valve. To start the car upward, 

the valve is moved past the stop- 
position and opens the exhaust-port 
between the bottom of the cylinder 
and the open tank, when the pres¬ 
sure from the high-pressure tank 
forces the piston down with a ve¬ 
locity regulated by the amount of 
opening in the exhaust-port. 

The duty of the pump is to 
transfer one cylinder full of water 
for each complete lift and return of 
the car, from the exhaust-tank to 
the high-pressure tank, in which 
the air is compressed to form the 
pressure-cushion. 

Another type of the hydraulic 
system is the multiple effect of a 
pushing or pulling piston upon a 
series of pulleys, by which a short horizontal or vertical cylinder will 
produce a lift of many times the traverse of the piston, or plunger. 



.VALVE 


PRFSS 


Fig. 339.—Hydraulic piston-elevator. 










































































374 


THE ELEVATOR AND ITS WORKING 


Fig. 341 illustrates a section and side view of the plunger type, in 
which A is the cylinder; P, the plunger; E i; E 2 , E 3 , the three sheaves, 
which have their duplicate at the bottom and their anchor-eye for the 
cable at K, giving a lift of 8 to 1; H, the valve-chest, with the three 
positions of the lever for start, stop, and reverse. R is an automatic 
stop on a valve-rod operated by the arm Q on the sheave-frame. 



Fig. 340.—Pressure-tank elevator-plant. 


The high-lift plunger-elevator (illustrated in Fig. 342) has been so 
perfected in its operation by experience with the failures of the tele¬ 
scopic lifts of the early hydraulic elevators that it has new attained 
a lift of 2S0 feet with a single plunger traversing a cylinder extending 
to a depth beneath the ground floor more than equal to the lift. These 
elevators run at speeds from 200 to 600 feet per minute; they carry a 
counterweight of 90 per cent, of the total load, and use a water- 
pressure of 185 pounds per square inch. 









































































































































































































































































THE ELEVATOR AND ITS WORKING 


The elevators in the Trinity 
Building, New York City, are of 
this type, with plungers 6J inches 
diameter and with an upward fric¬ 
tion of 500 pounds. 

The total weight of the high-lift 
car, plunger, and fixtures is 8,460 
pounds; full load, 1,600 pounds; 
total, 10,060 pounds. The counter¬ 
balance is 7,900 pounds, leaving 
2,660 pounds, including friction, to 
be lifted by 6,000 pounds water- 
pressure under the piston—suffi¬ 
cient for a speed of from 400 to 600 
feet per minute. 

Valves entirely independent of 
the main controlling-valve are pro¬ 
vided to bring the car to a gradual 
stop at each end of its travel. Two 
cables, one operating at the top of 
the run, the other at the bottom 






Fig. 341.—Plunger multiple lift. 


Exhaust 

Fig. 342.—High-lift plunger 





















































































































































































































































































376 


THE ELEVATOR AND ITS WORKING 



Fig. 343.—Three-way valve and pilot-valves. 



of the run, are connected with 
these automatic valves, as 
shown in the cut (Fig. 342). 

The overrun of the sheaves 
on the stop-cables causes their 
shortening, which lifts the 
weight e cl valve-levers and 
shuts off the supply-valve or 
exhaust-valve at the top or 
bottom of the car-run. 

The elevator is controlled 
by a lever in the car, and the 
main three-way valve is oper¬ 
ated by a pilot-valve, as illus¬ 
trated in Fig. 343. In this 
way an easy and perfect con¬ 
trol of the car is secured. 

In Fig. 344 are illustrated 
the pushing plunger type and 
its operation as connected to 
the passenger-car, complete 
with governor and automatic 
stop, with lever and double 
sheave, on the valve-lanyard 
in the car for control. 

This type is operated by 
the same combination of 
pump, open and closed tanks 
as shown in Fig. 340. 


Fig. 344.—Hydraulic elevator, horizontal plunger. 







































































































































































































































THE ELEVATOR AND ITS WORKING 


377 


In Fig. 345 is shown the safety-governor of the Otis elevator, by 
which a brake is applied to the governor-cable when the speed of 
the car exceeds the rate at which the governor is adjusted. 

Its action is independent of the lifting-cables, so that in case of 
a breakage of the cables it will bring into action the car safety-devices 
to which it is connected, and will bring the car to a safe and easy stop. 
The governor-cable is endless, passing over the driving-sheave of 
the governor and a weighted sheave at the bottom of the shaft. It 
has a spring-stop connected to the gravity wedge mechanism under 
the car; it arrests its descent when 
excessive speed is attained from any 
cause. 

Fig. 346 shows the mechanism of 
the governor-cable connection to the 
gravity-wedge device. A and B show 
the cable running over the governor- 
sheave; to the side A are attached 
stops and a helical spring to ease the 
contact with its engaged lever on a 
sudden change of speed. The lever 
operates the arm of a rock-shaft that 
extends to the wedge-levers on each 
side of the car. 

In Fig. 347 is represented the 
action of the gravity-wedge safety- 
device of the Otis Company. It is 
best described in their own words, 
which follow: 

u Under the car is a heavy hard- Fig. 345.—Otis automatic governor, 
wood safety-plank, on each end of 

which is an iron adjustable jaw, enclosing the guide on the guide-post. 
In this jaw is an iron wedge, withheld from contact with the guide 
in regular duty. Under the wedge is a rocker-arm, or equalizing-bar, 
with one of the lifting-cables attached independently at each extremity. 
The four lifting-cables, after being thus attached, pass over a wrought- 
iron girdle at the top of the car. Each cable carries an equal strain, 
and the breaking of any one cable puts the load on the othei cables, 
which throws the rocker out of the horizontal position, and foi cos the 






















































378 


THE ELEVATOR AND ITS WORKING 



wedges on both sides 
instantly and immov¬ 
ably between the iron 
jaws of the safety- 
plank and the side of 
the guides, stopping 
the car. It may be 
raised to any position 
by the unbroken ca¬ 
bles, though it cannot 
be lowered until a new 
cable is put on.” 

A is the elevator 
car-guide; B, safety- 
wedge; C, safety- 
wedge shoe; D, ad- 
j ustable gib; E, safety- 
i, i r x j • wedge back spring; 

Fig. 346.—Automatic governor controlled safety-device. 

F, r, shackle-rods on 

ends of cables; G, equalizing-bar; H, lever to lift the wedge; I, I, set¬ 
screws on the equalizing-bar for 
adjusting the lever H to lift the 
wedge, by either movement of the 
equalizing-bar, from the breaking 
or stretching of any one of the 
cables. 

In Fig. 348 is shown a section 
of the Otis Company’s vertical hy¬ 
draulic cylinder, circulating-pipe, 
valves, and valve-gear. The operat¬ 
ing-valve is balanced and moved 
by a rack-stem and a pinion on the 
shaft of the sheave carrying the car- 
lanyard. Pressure for operating is 
always full in the cylinder above 
the piston and in the circulating- 

pipe. _ 

The valve, as shown in the cut, Fig. 347.— Gravity-wedge safety-device. 












































































































































































































































































































































REFERENCES TO NUMBERED PARTS 



1. Travelling-sheave. 

2 Travelling-sheave bushing. 

3 Travelling-sheave pin. 

4. Travelling-sheave guard. 

5. Travelling-sheave strap. 

6. Oil-cup. 

7. Piston-rod cross-head. 

8. Stuffing-boxes. 

9. Air-cock. 

10. Drip-pipe. 

11. Curb on top head of cylinder. 

12. Piston-rods. 

13. Cylinder. 

14. Circulating-pipe. 

15. Piston. 

16. Top follower. 

17. Bottom follower. 

18. Piston air-valve. 

19. Piston-cup. 

20. |-inch square rubber packing. 

21. Set-screws for starting top follower 

when removing it to pack. 

22. Cylinder-legs. 

23. Drain from bottom of cylinder. 

24. Water-chest. 

25. Relief-valve, to relieve ram of 

water when the valve is sud¬ 
denly closed during the ascent 
of car. 

26. Valve-chamber. 

27. Valve-plunger, consisting of: A. 

Rack-follower; B. Valve-stem; 
C. Top to valve piston-cup; D. 
Bottom to valve piston-cup; E. 
Spider; F. Valve-cup packings. 

28. Valve-rack. 

29. Valve-rack shoe. 

30. Valve-pinion shaft. 

31. Valve-cap. 

32. Valve-glands on pinion-shaft. 

33. Valve-sheave. 

34. Check-valve. 











































































































































































































































































380 


THE ELEVATOR AND ITS WORKING 


is at 11 stop ” for the car; lowering it opens communication between 
the upper and lower sections of the cylinder, and the car descends by 
its own weight and by the transfer of the water from above to below 
the piston. By raising the valve the water beneath the piston dis¬ 
charges, and the higher pressure on the upper side of the piston sends 


the car upward. 

One of the later innovations in the elevator line has been brought 
out in the ramp, or escalator, a contrivance which affords a convenient 
way of getting upstairs. One of the earlier devices is shown in 






Fig. 349.—The ramp. 


Fig. 349, with sections of the upper and lower ends of the ramp with 
the driving-gear. A dynamo and a transmission device drive the 
upper drum and guards at a mean speed of 20 inches per second. 

The system comprises an endless web formed of bars of wood which 
are provided with rollers that are formed of a material called “ hema- 
cite ” and that run upon rails. The returning half is suspended from 
a rail lodged in the lower chord of the principal girder. This arrange¬ 
ment of chains with detachable links permits of doing away with 
stretchers. 


















































































































3S1 


THE ELEVATOR AND ITS WORKING 

The jointed web is actuated by a chain of which each link corre¬ 
sponds to one of the bars of wood. This passes at the upper part over 
an indented wheel actuated by the electric motor, with the interposition 
of a shaft with a ratchet to prevent any return in an opposite direction. 



Fig. 350.—The step-escalator. 


The jointed bars are provided with rubber projections for the 
purpose of giving the feet a firm hold. These projections, which are 
arranged in longitudinal bands, make their exit at the lower part 
and disappear at the upper between the teeth of metallic combs 
designed to take up and set down the passengers without jerks. The 
guards consist also of endless chains covered with rubber and cloth. 
Each link of the chain slides 
in a groove that prevents 
any lateral displacement. 

A perspective view of the 
lower end of the ramp in the 
lower section of the cut shows 
the jointed web, sprocket- 
drums, and hand-rail. 

In Fig. 350 is illustrated 
the newest type of escalator, 
brought out by the Otis 
Company, and in use on the 
Sixth Avenue Elevated Railroad and at the Macy department store 
in New York City. It will be seen that in this type the passengers 
step onto the escalator on an even moving floor that rises into steps 
at the incline, which again form an even floor at the top for a sufficient 



Fig. 351.—Worm-gear elevator. 

























































382 


THE ELEVATOR AND ITS WORKING 


distance to step off without trouble or danger. The hand-rail travels 
at the same rate as the steps. The capacity ranges from 4,000 to 
6,000 persons per hour. 

Many direct-cable elevators are driven through worm-gear which 
has its own drawbacks from wear and cutting of the gear. For safety 
in this respect the double worm-gear is in use, which reduces the fric¬ 
tion, serves the purpose of balancing the thrust of the driving-shaft, 
and is also a means of safety from breakage of teeth. The worms 
have right-and-left-hand threads. The Sprague type of electric-driven 
elevator is illustrated in Fig. 351. 

THE MASON ELEVATOR PUMP-PRESSURE 

REGULATOR 

This regulator, which is illustrated in Fig. 352, is designed for the 
larger sizes of steam-pumps operating hydraulic elevators. The im¬ 
portant feature in this machine is that it operates on the slightest 

change of pressure, opening 
and closing the steam-valve 
to its fullest extent prompt¬ 
ly and with certainty. 

Referring to the section¬ 
al view, Fig. 353, the opera¬ 
tion is as follows: Steam 
from the boiler enters the 
regulator at the inlet, and 
passes through the main 
valve into the pump, which 
continues in motion until 
the required water-pressure 
is obtained in the elevator 
system, which acts, through 
a J-inch pipe connected at 
A, upon the diaphragm B. 
This diaphragm is raised by 
the excess water-pressure, 
and carries with it the 
weighted lever, opening the 

































































































































































































































THE ELEVATOR AND ITS WORKING 


c 

o 

>> 


v 





auxiliary valve 1), and admitting the water-pressure from the con¬ 
nection E to the top of the piston, at the same time opening the 
exhaust-ports under the piston, thus allowing the water under the pis¬ 
ton to escape into the drip- 
pipe, thereby pushing the 
piston down, which closes 
the steam-valve and stops 
the pump. 

As soon as the pressure 
in the system is slightly re¬ 
duced, the lever, on account 
of the reduced pressure un¬ 
der the diaphragm, is forced 
down by the weight, carry¬ 
ing with it the auxiliary 
valve, thus ope n i n g the 
exhaust to the top of the 
piston, and at the same 
time admitting the water- 
pressure under the piston, 
which is now forced up 
and opens the steam-valve, 
again starting the pump. 

The main balanced valve 
and the controlling-valve are connected by an outside yoke, as are 
also the auxiliary valve D and the lever, as shown in Fig. 352. 



Fig. 353.—Section of pump-pressure regulator. 


AIR-COMPRESSORS AND COMPRESSED AIR 

The steam end of an air-compressor is essentially the same, in all its 
details, as that of other steam-engines, as explained in previous chap¬ 
ters of this work. The air end, and its action and operation, come 
within the province of the engineer, and require some consideration. 
In many places the distribution and use of compressed air also 
require some knowledge on the part of the engineer of its properties 
and action. For details of the uses and work of compressed air for all 
purposes, the author recommends reference to his large work on 

















































































































384 


THE ELEVATOR AND ITS WORKING 


“ Compressed Air/’ published by the N. W. Henley Publishing Com¬ 
pany, New York City. 

Compressed air is not only used for running local motors, hoists, 
and rock-drills, but is largely in use for refrigeration in the marine and 



Fig. 354.—Diagram of compression and expansion of air. 


the naval service. The compressed-air brake is at the fore in railway 
service. 

By compression and expansion air obeys the laws of thermody¬ 
namics, becoming hot by compression and cooling by expansion. 
For an assumed compression and expansion without change of tem¬ 
perature— isothermal— 
its volume and pressure 
10 are in exact inverse pro- 

6o portion, but in actual 

50 practice in the compres¬ 

sor and motor the lines 

ho 

of pressure and expan- 

30 

sion, as shown on an 
20 indicator - diagram, are 

io adiabatic to meet the 

conditions of tempera¬ 
ture. 



Fig. 355.—Two-stage compression. 
























































THE ELEVATOR AND ITS WORKING 


385 



Fig. 356. —Bennett air-compressor. 


In the diagram (Fig. 354) are shown the theoretical curves due to 
compression and expansion where there is no transfer of heat to or front 
the walls of the cylinder. The figures along the margin of the curves 
show the change of volume from the isothermal line. In actual 
practice the compression- 
volumes are less, and the 
expansion-volumes are some¬ 
what greater, than shown by 
the figures. 

The mean pressure due to 
compression and expansion, 
as taken by an indicator, can 
be figured in the same manner as with the steam-card (see Indicator, 
Chapter XIII), and needs no further explanation. Full details of the 
theory, practice, and work of compressed air are given in the work on 
“ Compressed Air and Its Uses” by the author. 

The effect of compressing air in compound or by two stages is 

shown in Fig. 355, and for high 
pressures a three-stage com¬ 
pression shows much economy 
in the power used for compres¬ 
sion. 

In the two-stage diagram 
it may be seen that the lower curve is that of the isothermal up to 80 
pounds per square inch, while the upper curve shows the increased 


■ e] 

- 

: c 


/* "..P... 




^o\ 

-, -ry 



Fig. 357.—Clayton compressor. 


volume due to compounding with an intercooler to shrink the volume 
before it enters the second cylinder. In this way the economy in 
power by compound compression up to 100 pounds is about 15 per 
cent., and increases with higher pressures. 



Fig. 358.—Corliss air-compressor. 




















































































































386 


THE ELEVATOR AND ITS WORKING 


The accompanying illustrations are those of some of the models 
and details of compressors in use. 



Fig. 359.—Duplex tandem air-compressor. 




In Fig. 356 is shown an elevation of the Bennett air-compressor, 
with direct piston-connection, cross-head, and outside connecting- 
rods to the crank-pins in the fly-wheels. The eccentric on the shaft at 

the rear of the steam-cylinder 
is linked to a vertical lever 
and valve-rod. 

In Fig. 357 is shown the 
elevation of an air-compressor 
of the Clayton type, in which 
the cylinders are placed at 

Fig. 360.—Ingersoll-Sergeant cylinder. each end of the bed frame > 

and with yoked piston-rod 

connection and with the crank and connecting-rod within the yoke. 

The direct-connected tandem system, with a Corliss steam-cylinder 
and centrifugal governor, is 
shown in Fig. 358. It is a type 
of air-compressor now rapidly 
increasing in economy and use¬ 
fulness by tandem compound¬ 
ing and cross - compounding, 
and is in use in large plants. 

An example of the duplex 
tandem type of air-compressor 
is shown in the plan (Fig. 

359). In this type the steam Fig. 361.—Vertical lift-valve cylinder. 




























































































































































































































































387 


the elevator and its working 

end is provided with a throttling-governor and riding-cutoff for each 
cylinder. 

The air-cylinders are of the Ingersoll-Sergeant pattern, set on a 
sole-plate and fastened by rods to the steam-cylinders. The piston- 
rods are connected by couplings, and the air-supply is regulated by 
a governor. 



Fig. 360 shows the cylinder, piston, and valves of the Ingersoll- 
Sergeant pattern. It has a through hollow piston-rod, into which the 
air is drawn to feed the hollow piston and cylinder through the annular 
valves, one of which is shown at G. These valves open and close by 
their momentum, and are free from obstructive pressure against the 
incoming air. 

Fig. 361 illustrates a section of an air-cylinder, with vertical lift- 











































































































































































































Fig. 363.—Reynolds-Corliss blowing-engine. 

Steeple type, condensing; long cross-head connections to piston-rods and crank- 
rods. The air-cylinder has mechanically operated valves. Built by the Allis- 
Chalmers Company lor blast-furnaces, smelters, and Bessemer work. 








































































































































































































































































































































































THE ELEVATOR AND ITS WORKING 


389 

valves controlled by springs, a solid piston, and with cylinder-heads 
water-jacketed. 

In Fig. 362 is shown an end-view sketch of the largest high-pressure 
air-compressor ever built. The steam-power of the compressor is 
derived from a duplex vertical cross-compound engine with Rey- 
nolds-Corliss valve-gear. With steam-pressure of 150 pounds and 40 
revolutions per minute, it is equal to 1,000 horse-power. Directly 
beneath each pair of steam-cylinders is placed a pair of air-cylinders, 
tandem, and connected to the steam-cylinder cross-heads by a yoke- 
frame. The steam-cylinders are 32- and 68-inch by 60-inch stroke. 
The air-cylinders are 46-, 24-, 14-, and 6-inch by 60-inch stroke; they 
are tandem in pairs and single-acting. The approximate capacity at 
the above speed is 2,269 cubic feet of free air per minute. The pressure 
in the first cooler is 40 pounds; second cooler, 180 pounds; third cooler, 
850 pounds, and in the after-cooler 2,300 pounds. It was built by the 
Allis-Chalmers and Ingersoll-Sergeant companies for the Metropolitan 
Railway Company, New York City, for charging the car-tanks and 
operating air-power cars. 

There is much acumen required in an engineer operating a large 
air-plant that is not usual in the experience of the young engineer, so 
that a special study should be made of the written or personal instruc¬ 
tions given by the builders of such plants, as their construction is as 
variable in detail as that of steam-plants. 

A type of the massive engines used for supplying air under 
pressure to the blast-furnaces of the iron industry is shown in Fig. 
363. The man on the floor represents a comparative proportion for 
the size of this colossal blowing-engine. 


CHAPTER XXII 


THE COST OF POWER-ECONOMY 


The subject of the cost of power for various mechanical uses 
and for electric power and lighting has been a theme of engineering 
papers and of discussion in technical journals for many years past, 
with varying results depending upon the varying conditions in the 
cost of material and labor. 

We append an abstract from a communication of Mr. William 0. 
Webber, of Boston, Mass., containing his experience in the matter of 
the cost of a steam-plant and the operating cost of plants of various 
sizes and types. The cost of land and buildings will probably make 
a material difference in estimating the total cost of power, and for the 
annual cost of operating, the insurance, interest, and repairs should 
enter into the items of expense. 

The following table shows the estimated cost of a plant in the 
Eastern States for a 60-brake horse-power: 


Table XLI. — Cost of a 60-Brake Horse-Power Plant 


Land for engine and boiler-room. 

Buildings for engine and boiler-room.... 

Chimney. 

80 horse-power boiler. 

Ash-pan for boiler (below high tide-level) 

Blow-off of sink. 

Boiler- and engine-settings. 

Damper-regulator.. 

Injector-tank. 

Water-meter. 

Piping. 

Pump. 

Feed-water heater..... 

Pipe-covering. 

Engine 12 x 30. 

Pan for engine-flywheel. 

Steam-separator. 

Oil-separator. 

Piping, freight, and cartage. 

Shafting in place. 

Belting in place. 




$2,500 

.00 



2,500. 

.00 



1,200. 

.00 

$790, 

.00 



. 120 

.00 



31 

.00 



1,282 

.00 



75. 

00 



10 

.00 



60 

.00 



22 

.13 



146 

.50 



70. 

40 



70. 

75 


* 



2,677. 

78 

1,065 

.00 



72. 

00 



60. 

.00 



41. 

.80 



1,026. 

.41 





2,265. 

.21 

550 

.00 



285. 

.00 





835. 

00 



$11,977. 

,99 


11,977.99 

60 


= $199.61, or say $111 per brake horse-power for the machinery alone. 


390 




























Table XLII. —Cost of Steam Horse-Power per 1 Brake Horse-Power per Annum. 

William 0. Webber. 


THE COST OF POWER-ECONOMY 


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The above and following tables are the result of late experience, and include the average cost of land and build¬ 
ings necessary for the steam-plants upon which the reports of steam-power plants for factoiies have been based. 
The approximate ratio is 1 indicated horse-power = .85-brake horse-power for small powers; less for the large 

power-plants. 























































































392 


THE COST OF POWER-ECONOMY 


The annual cost per brake horse-power, of operating the ordinary 
types of steam-plants under 200 horse-power may be stated as follows: 


Table XLIII. —Operating Expenses. 


Average 

horse-power. 

Cost of coal per 
ton, 2,240 pounds. 

Total cost 
per annum. 

Remarks. 

182 

$3.50 

$57.59 

No land or building costs. 

133 

3.25 

60.00 

“ “ cost. 

100 

3.50 

65.00 

“ “or building costs. • 

97 

4.45 

86.80 

All costs included. 

75 

2.90 

92.40 

No land or building costs. 

50 

4.75 

111.05 

U U U U (C 

20 

4.45 

133.50 

All costs included. 


EFFECT OF LOAD-FACTOR ON THE COST OF POWER 


For an electrical system the great desideratum is a high load- 
factor with consequent greatest return on investment, load-factor 
being the ratio of average to maximum load. All the factors of expense 

included in cost of power to the 



consumer are then operating at 
maximum economy, and cost 
of power is at a minimum. 

In Fig. 364 is a diagram 
showing the total operating ex¬ 
penses, labor repairs and sup¬ 
plies, and fixed charges in 
curves representing the cost in 
cents per kilowatt hour for full¬ 
load and under-load conditions. 

In Fig. 365 is also a diagram 
for the same conditions in a 
non-condensing plant, in which 
it may be observed that the two 
^ lower curves are the same as 

watt condensing steam-plant. 10SC m Fig. 364, and that the 

uppermost curve represents the 
increased cost due to the steam end of the plant. 

Lighting of residences and offices produces a peak in the late after- 


.8 


.7 .6 .5 .4 

LOAD FACTOR 


.3 













































































































































































THE COST OF POWER-ECONOMY 


393 


noon and evening, with but little load the remainder of the twenty- 
four hours; consequently the average load on the plant with lighting 
only is small and the load-factor low. A commercial motor-load in 
connection with lighting will increase the average load even though 
causing a greater peak. The addition of a street-railway load still 
further increases the day load, 
but in consequence of the heavy- 
demand load during the rush- 
hours, when the public is going 
to and from business, which oc¬ 
curs at the peak of the lighting- 
load, the peak-load on the plant 
is greatly increased. This heavy 
peak, with but a small average 
load over the twenty-four hours, 
produces a low load-factor, as a 
portion of the machinery is shut 
down the greater part of the 
time. 

In the cost of power to the 
consumer various expenses are 
involved, viz., management, dis¬ 
tribution, and production. 

For a given system with given peak-load the cost of management 
is practically constant, no matter what the load-factor. 

Cost of distribution is constant with various load-factors in so far 
as the fixed charges and maintenance are concerned. The losses 
in distribution, however, vary, these consisting of losses in lines, trans¬ 
formers if alternating current is used, meters, losses in grounds, and 
losses from theft of current. 



Fig. 365.—Operating expenses of a 900- 
kilowatt non-condensing steam-plant. 


As to cost of production, the higher the load-factor the greater is 
the amount of power produced, the longer does the apparatus operate 
at best efficiency, the lower the ratio of fixed charges to total operating 
expenses, and consequently the lower the cost ot power per unit. 









































































































































































394 


THE COST OF POWER-ECONOMY 


ECONOMICAL SUGGESTIONS IN THE 
GENERATION AND USE OF STEAM 
FOR POWER PURPOSES 

Although it is difficult to give any general information on this 
subject which will be of use or interest in the great variety of particular 
cases, it may be of some interest, and possibly of assistance to those 
who are managing or operating power-plants, to discuss some of 
the principles upon which economy in the use of steam depends. 

Beginning with the boiler, which is the first step in the production 
of power from fuel, it may be laid down as a good rule that it is more 
economical to use boilers of reasonably large size than to subdivide 
into a larger number of small units. The length and area of grate 
that can be conveniently fired or kept evenly covered with coal are, 
perhaps, the limiting features, if hand-firing is to be used. Working 
from this rule, a grate should not be over 7 feet long or more than 5 
feet wide, which would give 35 square feet of grate-surface. The 
quantity of coal that may be burned on such a grate varies widely 
with the kind of fuel and strength of draught. Using bituminous 
slack coal of fair quality/ with good natural draught or moderate- 
induced draught, it should be possible to burn 25 pounds of coal 
per square foot of grate per hour, or 875 pounds of coal per hour for 
35 square feet, and if this coal will evaporate say 8 pounds of water per 
pound of coal, the boiler, if constructed with heating-surface in proper 
proportion, would evaporate 7,000 pounds of water per hour, which 
would be equal to a little over 200 standard boiler horse-power. In 
order to give good economy, the boiler should have from 2,000 to 2,400 
square feet of heating-surface to evaporate this quantity of water 
economically. The return tubular boiler, on account of the amount of 
tube-surface in proportion to the direct surface exposed to the fire, 
should have not less than 12 square feet per horse-power; the water- 
tube type, from 10 to 11, and the internally fired type, which has a 
larger amount of direct heating-surface in the furnace and tubes than 
either of the others, should have 9 to 10. If the grate-surface is larger 
than that described, probably the grate will not be evenly covered 
with coal, or the fire will be dead in spots, so that too much cold 
air will pass through. 


THE COST OF POWER-ECONOMY 


395 

The economy in burning fuel is a matter requiring great skill 
and experience, and depends entirely upon the evenness, thickness, 
and condition of the fire, which controls entirely the air-supply and, 
therefore, the perfection or imperfection of the combustion. 

It is too often the case that the demands for increased horse-power 
are met by grate-surface too large in proportion to the heating-sur¬ 
face of the boiler or forced draught, and too little attention is given 
to careful firing, with heating- and grate-surfaces in proper propor¬ 
tion to give best economy, and frequently a great deal of money is 
spent in obtaining high-class engines and condensers, whereas the 
principal loss is in the boiler and fire-room. 

The question is often asked whether in case of installing a certain 
horse-power of boilers, say 300 horse-power, it would be more econom¬ 
ical to have three boilers of 100 horse-power each or two boilers of 
150 horse-power each. We would advise to have the two larger units, 
as it will always be found that the larger boilers have less radiation, 
less air-leakage, and better combustion than a corresponding horse¬ 
power in small units. If it is necessary to have a spare unit for cleaning, 
let there be another one provided of the same size. 

In regard to the pressure to be carried, it is well known that a 
high pressure gives a greater amount of expansion and better economy 
in proportion to the fuel burned. Even with simple engines in which 
'it is not possible to obtain the full advantage of expansion, the high 
pressure of steam, which is drier and contains a larger number of 
heat-units in proportion to the volume, gives the best results. Every 
boiler should be designed for not less than 150 pounds pressure per 
square inch. Even if it is not possible to utilize the full pressure, the 
boiler will be stronger, last longer, and be a better investment in the 
long run. In this respect the water-tube, boiler, or some form of 
internally fired boiler in which the shell-plates are not exposed to the 
high temperature of the furnace, is certainly safer than the horizontal 
return tubular boiler, because for large units intended to carry high 
pressure the shell-plates and seams must be of considerable thickness, 
which, being directly exposed to the hottest part of the fire, are liable 
to give trouble, especially if there be any scale or sediment in the water 
which may settle on the bottom directly over the fire. 

As to the economy of various types of boilers, experience shows 
that all of the standard types—horizontal return tubular, water-tube, 


THE COST OF POWER-ECONOMY 


396 


or internally fired—if they are designed with proper proportions of 
heating- and grate-surface, give about the same evaporation per 
pound of coal, provided they are in good condition and clean both on 
the fire- and on the water-surface. While the externally fired boilers, 
either of the return tubular or the water-tube type, are said to have 
some advantage in combustion, on account of the heat of the brick 
furnace, they are subject to losses which are more serious in the way 
of air-leakage in the setting and radiation. 


The repairs and cost of keeping up brick furnaces are considerable, 
and as a result of deterioration there is more or less air-leakage through 
the brickwork going on constantly. In this respect the internally 
fired boiler has a great advantage over return tubular or water-tube 
boilers with brick furnaces, as it will be just as efficient after continued 


use as when first started. 

In any type of boiler it is of great importance to keep the tubes 
and other surfaces free of soot and scale. Otherwise a large loss may 
be sustained. It is a mistake to depend entirely on the steam-blower 
or tube-cleaner, which only removes the loose soot, a scraper being 
necessary for occasional use to free the hard scale; otherwise it will in 
time accumulate on the fire-surfaces. It is necessary to point out that 
scale, or, worse still, oil on the inside of a boiler may be a source of 
great loss, experience having proved that even a thin film of oil will 
so prevent the transfer of heat that the plates or tubes will be burned 
in a short time. Nothing but pure water should be used for making 
steam, and the practice of making the boiler do duty as a water- 
purifier as well as a steam-generator cannot be too strongly condemned. 
If the owners of steam-plants could realize that a very small deposit 
of soot on the outside and scale on the inside mean a loss of from 10 
to 20 per cent, of the total fuel-consumption, they would be con¬ 
vinced that it would be much cheaper to spend money in purifying 
apparatus, so that the scale or sediment will be removed before the 
water is fed to the boiler. 

The next step to be considered is the heating of the feed-water. 
This may be accomplished in two or three ways: first, by means of 
the exhaust-steam, which, coming from a non-condensing engine, is 
capable of heating the feed-water to 212° F. and of saving say 12 to 
15 per cent, as compared with feeding cold water. For large plants 
where it would be advisable to use induced draught to make up for the 


THE COST OF POWER-ECONOMY 


397 


loss in temperature of the chimney-gases, which produce the draught, 
it will undoubtedly pay to use an economizer; but as this apparatus is 
expensive both in first cost and in up-keep, the amount saved in utiliz¬ 
ing the waste gases from a small plant would probably not offset the 
outlay. The closed type of feed-water heater is about as efficient as 
the open type, provided the water is pure, and it avoids trouble from 
pumping hot water, but the open type is frequently made use of to 
assist in purifying the water and, if properly managed, may give good 
service in that respect. For condensing-engines a primary heater 
of the closed type may be installed between the engine and condenser, 
which will help to condense the steam and heat the feed-water to a 
low temperature—say 130 to 140° F. A secondary heater, either 
of the closed or the open type, may be used to heat the feed-water to 
a still higher temperature, say 212° F., by the use of the exhaust from 
the feed- and air-pumps, which exhaust cannot be used more profitably 
than in this way, as all the heat is returned to the boiler. 

In regard to the type of engine used for the plants, if the size of the 
plant is sufficient, and the work comparatively steady, the highest 
possible results may be obtained from compound condensing-engines 
using the highest possible pressure of steam, but under other conditions, 
such as variable load or low pressure of steam, it may be quite possible 
that the simple engine will give better results and cost less for repairs. 
With low steam-pressure, non-condensing, there is certainly nothing 
better or more economical than a single-cylinder Corliss engine where 
it can be installed to advantage. In the case of direct-driven electric 
units of small size, it is necessary to use high- or medium-speed engines, 
both on account of the loss in friction that would result if counter¬ 
shaft and belting are used and because the higher-speed machines will 
give the best regulation. For small units up to say 75 or even 100 
horse-power, there is nothing better than the modern high-speed 
automatic engine, provided it is of good design, not overloaded, and 
not overspeeded. 

As illustrating the slight wear of high-speed engines under favorable 
conditions, a Robb-Armstrong engine of 12-inch stroke, which has 
been running at 275 revolutions per minute for electric lighting for 
twelve or fourteen years, shows only about two-thousandths of an 
inch wear of the journals and six-thousandths of an inch wear of the 
shaft-bearings. 


398 


THE COST OF POWER-ECONOMY 


Unfortunately, this class of engine is so frequently overloaded 
and overspeeded that it gives poor results and gets a bad name, whereas 
the Corliss slow-speed type of engine is limited both in the matter of 
speed and horse-power, because the cut-off of the single-eccentric type 
will not go much beyond half-stroke, and in that way the engine is 
saved from overloading and abuse, and this is, perhaps, one of its 
many advantages. A compound engine is not suited to low pressure 
or irregular loads, and the extra cylinder and complication of parts 
are a great objection under such conditions. When a condenser is 
used, even with low pressure and somewhat irregular loads, it may 
be employed to advantage, whereas with high pressure, say from 125 
to 150 pounds or over, the non-condensing compound will give the 
best results, unless the load is very irregular and running to light loads 
a large part of the time. 

The question is sometimes asked whether it pays to reduce the pres¬ 
sure when the load is light. From experience, we do not believe it 
pays to reduce the pressure on the boiler, excepting in very extreme 
cases, but if it can be done by throttling before the steam reaches the 
cylinder of the engine, it would be an advantage, because this retains 
the heat-units due to the higher pressure in the steam and the throttling 
has a slight superheating effect. 

Another source of considerable loss in the operation of steam- 
plants, particularly large ones, are the insufficient size of piping (caus¬ 
ing the pressure to be reduced between the boiler and engine), and im¬ 
perfect drainage, which is an enemy both to economy and to the life of 
the engine. In many of the newer plants it has been found a great 
advantage to install receivers to equalize the pressure and to collect 
the water before it reaches the engine. 

In general it may be said that the principal cause for loss in steam- 
plants is the use of engines which are overloaded or unsuited to the 
conditions of work, undersized, or which have badly arranged steam- 
and exhaust-pipes. Other frequent causes are the imperfect condition 
and poor operation of the boilers. In many plants exhaust-steam, 
which might be utilized for heating, is wasted, and in others, where the 
exhaust-steam is utilized for heating, power is wasted by excessive 
back pressure. The most economical use that exhaust-steam can be 
put to is for heating, because thereby all the latent heat-units are 
made use of, but it should be done without back pressure on the engine, 


THE COST OF TOWER-ECONOMY 


399 


by means of a vacuum system to draw the steam and water through 
the heating-pipes; otherwise there will be a loss both of fuel and of 
power, due to the engine working under imperfect conditions. 

The system in general use for heating by exhaust-steam is by 
means of coils of pipe around the walls or overhead in factories and 
mills and by radiators in offices and private rooms. 

If the space to be heated is not excessively large, the back pres¬ 
sure on the engine should not exceed 2 or 3 pounds per square inch, 
and may not exceed \ pound with the proper-sized exhaust-pipe and 
coil-connections. 

The most serious trouble from back pressure in an exhaust heat¬ 
ing-plant has been remedied by enlarging the area of the exhaust- 
pipe and of all the pipe-connections to the coils, so that the inlet of 
each coil is as large as or larger than the total area in each of the 
radiating-coils, resulting in the reduction of the back pressure from 
4 pounds to j pound per square inch. 


CHAPTER XXIII 


THE ENGINEER AND HIS DUTIES 

We cannot here enter into a description of the innumerable details 
and intricacies involved in the proper care of a steam-plant, such 
details and conditions having been very fully illustrated and described 
throughout the foregoing chapters of this work. The minor details and 
the knowledge required for operating a steam plant and for detecting 
or obviating the troubles and defects constantly arising therein are 
fully explained in the question-and-answer form in the many books on 
this subject, such as “ Combustion of Coal ” by Barr, and “ Engine- 
Runners’ Catechism ” and “ Steam-Engine Catechism ” by Grimshaw 
—most interesting books for students and young engineers. Their 
study often affords hints useful to older heads, so that every engineer, 
on taking charge, should be thoroughly posted on the requirements of 
his profession in proportion to the extent of the duties assigned to him. 

If all the duties devolve upon one person, as in small plants, the 
operating details, through all the steps from the coal-heaver to the 
expert steam-user, should be at his command, and if in charge of a 
large plant, where firemen, water-tenders, oilmen, cleaners, and 
machinists in repair-work are employed, his knowledge of the require¬ 
ments of all detail work in the construction of the plant should not 
only be of the expert kind, but should also involve a large experience 
in the whole range of construction, its theory and practice, in steam- 
engineering. If an electrical-generating and transmission plant is in 
connection with a power-plant, he should be also an electrical expert 
that he may readily meet the contingencies that may occur in any 
part of a complex power-installation. 

The license system is doing much for the education of engineers 
in the line of their duty, as its requirements impose an effort in study 
that would otherwise be neglected. 

License is now required in the States of Massachusetts, New York, 
Ohio, Illinois, Wisconsin, Missouri, Minnesota, Kansas, Montana, and 

other States. Municipal license is required in many of the large cities. 

400 


THE ENGINEER AND HIS DUTIES 


401 


KNOCKING AND OTHER NOISES IN THE ENGINE 

The causes of knocking or other noises in a steam-engine are 
anxieties to the careful engineer from their numerous locations and 
signs of possible danger. They may be generally traced by the ear, or 
by the feeling of the hand or fingers in contact with different parts 
where possibly loose joints may occur, and in obscure cases by a small 
stick of hard wood placed between the suspected point and the fingers 
or teeth. 

Some of these causes may be enumerated, commencing with the 
cylinder-head. Water in the cylinder gives a peculiar sound—a rush 
and a blow—while the contact of solid pieces gives a click or thump 
the character of which a little experience soon reveals. Looseness in 
the piston-rings; looseness in the follower; rattling of nuts, set-screws, 
or springs used to set out the packing-rings, by being cast adrift in 
the chambers of the spider section of the piston, produce a constant 
click at every stroke. Other causes of noise are looseness of the rod 
in the piston through faulty fastening; looseness of the end of the 
valve-rod in the valve-connection in the steam-chest or in any of its 
joints, direct or through a rocker-arm; looseness in the cross-head 
boxes and bearings, piston-rod key, or lock-nut. Oval bearings, bound 
brasses, and side-thrust should be examined, particularly the last- 
named at the crank-pin. Main journals on crank-end of shafts may 
wear and have a thrust-jar. Looseness in the side-bearings of the fly¬ 
wheel key and a loose joint in the made-up parts of a fly-wheel have 
sometimes been a mystery to find. Squeaking anywhere shows the 
want of oil. 

don’ts for engineers and firemen 

Don’t forget to look at the water-gauge or to try the gauge-cocks 
the first thing in the morning. 

Don’t forget to open the drip-cocks before opening the throttle, 
which should only be just started from its seat to allow the cylinder 

to warm up and discharge water. 

Don’t neglect to start the blow-off every morning, before pulling 
forward the banked fire, to clean out any sediment that may have 


402 


THE ENGINEER AND HIS DUTIES 


accumulated in the blow-off pipe from the use of muddy feed-water. 
Once a week will suffice for good water; and 

Don’t forget to blow off boilers, surface and bottom, if so arranged, 
at stated times, to suit the nature of the water in use. 

Don’t allow steam-traps on the cylinder or cylinders of one engine 
to be connected in any way to the steam-trap or discharge-pipe of any 
other engine, thereby causing water to be drawn back into a cylinder 
when the engine is stopped. Such neglect has caused a wrecked 
engine. 

Don’t forget to lift the safety-valve off its seat at least once every 
day, nor neglect to rig a lanyard from the end of the lever to a con¬ 
venient place for this purpose. 

Don’t neglect to provide means for quickly closing the water- 
gauge valves when the glass breaks, if they are not automatic. 

Don’t forget your regular times for firing and for cleaning fires, 
and don’t allow holes to burn in the fire-bed. 

Don’t let the ashes accumulate under the grate—choking burns 
the bars; have stated times for cleaning. 

Don’t forget to look at the water-gauge or to try the gauge-cocks 
often, and don’t fail to regulate the running speed of the boiler-pump 
or injector to suit the requirement of an even water-level. A constant 
feed is best. 

Don’t forget to regulate the dampers and doors exactly to produce 
an even rate of combustion; if automatic dampers are in use, they 
should be often examined. 

Don’t neglect to blow out the steam- or water-gauge connection 
and also the pressure-gauge connection as often as needed to keep 
them free from obstruction. 

Don’t neglect to clean boilers at proper times to suit the kind of 
water used, by first drawing the fires, and, if brick-set, allowing 
sufficient time to cool the walls below damaging heat by opening the 
doors and dampers; then blow out and open the man- and hand-hole 
plates, and scrape out the scale and slush with a long hoe, and wash 
out with a strong stream of water from a hose. 

Don t forget to see that the blow-off pipe is clear of obstruction 
after cleaning boiler by drawing water through it. 

Don’t neglect to clean the boiler-tubes as often as once a week, 
and in some cases twice or three times a week, according to the draught 


THE ENGINEER AND HIS DUTIES 403 

of the chimney. A strong draught deposits less ashes in the tubes 
than a weak one. 

Don’t neglect to pump up your boiler to the upper gauge-line 
when stopping the engine at night. Start the pump before closing 
the throttle. 

*» 

Don’t forget to anticipate the stopping of the engine by throwing 
open the fire-doors, partly closing the draught-doors, and opening 
the dampers, and by spreading a little coal over the fire to prevent the 
sudden rising of the steam-pressure; then clean and bank fires. 

Don’t hang any old piece of iron on the safety-valve lever to stop 
sizzling. It’s a dangerous practice. If the valve leaks regrind it. 

Don’t neglect to search for and find the cause of any unusual 
occurrence, noise, or knocking in the engine or boiler-pumps, nor 
put off the remedy to some more convenient time. To-day’s doctor 
may prevent to-morrow’s disaster. 


QUESTIONS AND ANSWERS 

The newly fledged engineer applying for a license cannot be ex¬ 
pected to answer the thousand and one questions that may be contained 
in the catechisms of the examiners or inspectors, nor to understand the 
whys and wherefores of the elementary strength and construction of 
the machinery of the plant that he is to take charge of. It is sufficient 
if he has at hand the ready wit to operate and care for it and to know 
when it is running right or wrong, and what to do when confronted 
with the usual troubles of a power-plant. The progressive engineer 
has a vast field before him in which to explore the details of theoretical 
and constructive engineering that may lead him to the head of his 
profession. 

We append a limited number of the leading questions and answers 
of vital interest to applicants; but in publishing them do not wish 
to depreciate the full study of the subject as shown in the published 
catechisms and text-books. 

Question.—What is the most essential part of a steam-plant ? 

Answer.—The boiler, whose fire and water, by means of the heat 
of combustion, generate steam under pressure, which steam, by its 
expansive force in an engine, creates power. 


404 


THE ENGINEER AND HIS DUTIES 


Question.—What do you understand by combustion? 

Answer.—Combustion is the production of heat by the union of 
the oxygen of the air with the carbon of the coal in the fire. 

Question.—What is heat as you understand it? 

Answer.—Heat is a property of matter as measured by its tem¬ 
perature, and the quantity of heat that matter can hold with its 
change of temperature. 

Question.—Are there any other designations in regard to heat or 
its property? 

Answer.—Yes; specific heat, which is the capacity of any body in 
units of heat to raise 1 pound of it 1° by the Fahrenheit scale; sensible 
heat, which is the measure of heat as indicated by the thermometer; 
and latent heat, which is the unit quantity of heat required to vaporize 
liquids or fuse solids per pound of their weight. 

Question.—What is a unit of heat? 

Answer.—A unit of heat is the standard of heat-measurement, and 
is equal to the quantity required to raise 1 pound of water 1° by the 
Fahrenheit scale, or from 39 to 40° F. 

Question.—What are the essential requirements in the management 
of the fire under a boiler? 

Answer.—A clean coal-bed and just enough air to produce perfect 
combustion. 

Question.—What do you consider perfect combustion? 

Answer.—The hottest condition of the fire, which requires 2 pounds 
of oxygen for the perfect combustion of 1 pound of coal. 

Question.—How much air is required per pound of coal? 

Answer.—As about one-quarter of the air is oxygen, it will require 
10 pounds of air, or 130 cubic feet; but as the nitrogen of the air ob¬ 
structs combustion, the best practice requires about 195 cubic feet 
of air per pound of coal fed to the furnace. 

Question.—What is the effect of too much air fed to the fire? 

Answer.—It has a cooling effect; as only the exact amount of its 
oxygen can be taken up by the coal to form carbonic-acid gas, any 
excess of air dilutes and cools the gases formed by combustion before 
they come in contact with the heating-surface of the boiler. 

Question.—What is the effect if too little air is fed to the fire? 

Answer.—The combustion is imperfect, and carbonic-oxide gas 
is formed of one-third of the heating-power, due to the coal, which 
becomes explosive by the admixture of fresh air. 


THE ENGINEER AND HIS DUTIES 


405 


Question.—What are the constituents of the gases from a boiler- 
furnace? 

Answer.—Principally carbonic-acid gas (C0 2 ), carbonic oxide 
(CO), nitrogen (N), unconsumed oxygen and its nitrogen (excess of 
air), and steam from the moisture in the coal and air. 

Question.—What effect has moisture or wet coal on combustion? 

Answer.—They absorb heat by evaporation into steam, and retard 
the heat of combustion. 

Question.—What are the safety-appliances usually attached to a 
boiler ? 

Answer.—Safety-valve, three gauge-cocks, water-gauge, pressure- 
gauge, and sometimes a draught-regulator, fusible plugs, and a low- 
water alarm. 

Question.—How should a safety-valve be set? 

Answer.—To blow off at or below the legal pressure allowed for 
the boiler. If a much lower pressure is used, 5 pounds above the usual 
requirement will be sufficient. 

Question.—How should the water-gauge and gauge-cocks be set? 

Answer.—So that the middle of the glass and the middle gauge- 
cock should be on a level with the proper water-level in the boiler—say 
from 4 to 6 inches above the tubes, according to the size of the boiler. 

Question.—Where should the blow-off be attached to a boiler? 

Answer.—At the back end, to the bottom of the back head, or to 
the shell for best effect; sometimes at the front head, with or without 
an extension-pipe reaching to the back of the boiler. A surface or scum 
blow-off is also desirable to discharge from the water-level. 

Question.—What is a fusible plug, and what its use? 

Answer.—A screw-thimble of hard brass, filled with pure Banca tin, 
which melts at 442° F., and usually screwed into the crown-sheet 
of locomotive-boilers to give an alarm by melting and blowing out 
when the water-level falls below the crown-sheet. 

Question.—What is a steam-drum, and what its use? 

Answer.—A reservoir from which usually to supply dry steam, but 
of doubtful value on boilers of full capacity for their work, as the drum 
weakens the shell. 

Question.—What is a dry pipe, and what its use? 

Answer.—A perforated pipe along the upper part of the steam- 
chamber of a boiler for distributing the area of the steam-inlet to the 



406 


THE ENGINEER AND HIS DUTIES 


steam-pipe, and thus preventing the priming or entrained water from 
entering. 

Question.—What is an automatic damper, and what its use? 

Answer.—A damper that is operated by the pressure in the boiler 
acting upon a regulator that opens and closes the damper, and thus 
controls the draught to equalize the boiler-pressure. 

Question.—What is the effect upon the water-line of suddenly 
opening the throttle or the safety-valve ? 

Answer.—With small steam-room in the boiler and high pressure, 
the water would swell up by the liberation of steam, show a rise in the 
water-gauge, and probably carry water over to the engine, or discharge 
water from the safety-valve in case it was lifted. 

Question.—What are the first requirements of an engineer or fire¬ 
man when he enters the boiler-room in the morning? 

Answer.—To try the gauge-cocks and open the water-gauge 
valves and the drip-valve to make sure of the water-level, and clear 
the gauge-glass connection. See that all valves are set properly as 
well as the damper; and if the fire has been banked, haul it forward 
and start it. Overhaul the pump and oil it; as soon as there is steam 
enough, start the pump running slowly; and do likewise with the in¬ 
jector, so that all may be ready at the time for starting the engine. 
See that all oil-cups have eil, and that all parts of the engine are 
ready to start; then open the throttle just enough to clear it and the 
pipes from water, the drip-cocks also being open, and warm up the 
engine under its slowest possible motion. Give it time—if a small one, 
one or two minutes, and if a large one, three to five minutes—to grad¬ 
ually get up to speed after the engine is warmed up and clear of water. 

Question.—What is the effect of a surplus of air fed to a boiler- 
furnace? 

Answer.—Air in excess of the amount necessary for perfect com¬ 
bustion tends t.o cool the furnace by abstracting heat from the gases of 
combustion. 

Question.—What is the effect of feeding wet coal to the furnace? 

Answer.—The water in the wet coal absorbs heat by evaporation, 
which does not produce combustion and the high temperature due to 
combustion, and therefore has a cooling effect upon the furnace. 

Question.—In what direction is the steam-pressure in a boiler 
exerted ? 

Answer.—In all directions. 


THE ENGINEER AND HIS DUTIES 


407 


Question. What part of a boiler has the greatest pressure? 

Answer. In the steam-space the pressure is equal in all directions; 
in the water-space the hydrostatic pressure of the water must be 
added to the steam-pressure. 

Question.—How much is the hydrostatic pressure? 

Answer. It is equal to of a pound per square inch for every 
foot in depth. 

Question.—If the upper valve on a water-gauge were closed, what 
would occur? 

Answer.—The water would rise to the top of the gauge. 

Question.—Why would the water rise? 

Answer.—Because the steam above the water would cool, and its 
condensation would draw the water up. 

Question.—What would be the effect of closing the lower valve only ? 

Answer.—The gauge would gradually fill up by condensation. 

Question.—What would you do if you found the water out of sight 
in the water-gauge? 

Answer.—Try the lower gauge-cock, then open the drip-cock to the 
water-gauge. If no water, stop the engine, throw open the fire-doors, 
damp the fire with ashes or coal, and feel the check-valve to find if the 
pump is feeding. If not, examine the pump, and if it has occasioned 
the trouble, start it running very slowly, when, if water appears in the 
water-gauge drip-cock, increase the pump-speed until water appears in 
the gauge-glass, whereupon regulate the fire and start the engine. 

Question.—What would you do if the boiler commenced to foam 
excessively, or the water-gauge showed excessive motion? 

Answer.—In ordinary cases increase the feed and blow-off to clear 
the water; if not found sufficient, check the fire, stop the engine, and 
prepare to clean the boiler. 

Question.—What are the general causes for the foaming of boilers 
with good feed-water? 

Answer.—The forcing of boilers that are too small for the work 
assigned them, dirty or greasy water, and boiler-cleaning compounds. 

Question.—What would you do if you had a full head of steam 
and a good fire, and had to shut down suddenly? 

Answer.—Open the fire-doors and cover the fire with ashes or coal, 
start or increase the pump-speed, and if the steam is still rising in 
pressure, lift the safety-valve. 


408 


THE ENGINEER AND HIS DUTIES 


Question.—What effect has the steam from a foaming boiler upon 
the engine? 

Answer.—It carries water to the engine, which, by becoming solid 
in the pipe and steam-chest, is liable to wreck the engine by its solid 
filling of the clearance and compression-space. It is also wasteful of 
fuel. 

Question.—Suppose that the pump was running and the water 
was going down in the boiler. What might be the cause and where 
would you look for it? 

Answer.—Increase the speed of the pump and feel the check- 
valve to find if it is working, or try the test-cock on the force-pipe; 
find if the water-supply had failed; if there was no action of the pump, 
examine the pump-valves for faulty action; and, if necessary, stop 
the engine, slacken the fire, and overhaul the pump and water-supply; 
also examine the blow-off for leaks. 

Question.—How would you find if the pump was not drawing 
water, or whether there was a stoppage in the suction-pipe? 

Answer.—By rapping on the suction-pipe to find whether, by the 
sound, it is empty. 

Question.—If you were feeding with an injector and it failed to 
feed, what would you do? 

Answer.—Open the overflow and find if it were discharging. If 
not discharging, examine the water-supply. If steam were not dis¬ 
charging, open the injector and clean out the passages. Look after 
the boiler condition and its safety. 

Question.—How often would you clean the tubes of a boiler? 

Answer.—That would depend upon the kind of fuel and upon the 
chimney-draught; a strong draught tends to clear the tubes. With 
soft coal and weak draught, every other day with a steam-blower or 
brush; with anthracite coal, once a week is sometimes sufficient. 

Question.—How often should a boiler be cleaned? 

Answer.—That depends upon the kind of water used. With hard 
water, once in two weeks, with a daily blow-off; with soft, clear river 
water, once a month, with a blow-off every other day. 

Question. What is the difference between gauge-pressure and 
absolute pressure ? 

Answer. Gauge-pressure is zero at atmospheric pressure, while 
absolute pressure starts from a perfect vacuum—14.7 pounds per 
square inch less than the mean atmospheric pressure. 


THE ENGINEER AND HIS DUTIES 


409 


Question.—What is the initial cylinder-pressure? 

Answer.—It may ordinarily be the gauge-pressure in the cylinder 
at the beginning of the stroke, or, for the purposes of computation, the 
absolute pressure at that time. 

Question.—What is back pressure? 

Answer.—It is the retarding pressure on the piston during the 
stroke. In non-condensing engines it is that of the exhaust above 
atmospheric pressure, while in condensing-engines it is counted from 
a perfect vacuum. 

Question.—What is the mean pressure in a cylinder? 

Answer.—It is the mean forward pressure of the initial and expand¬ 
ing steam, less the mean back pressure from the exhaust above at¬ 
mospheric pressure, or in absolute pressure above a vacuum. 

Question.—What is clearance? 

Answer.—It is the difference between the volume of the piston- 
displacement and the volume of the cylinder- and steam-passages, 
and varies from 2 to 8 per cent, of the piston-displacement in vari¬ 
ous types of engines. Its economy is inversely proportionate to its 
volume. 

Question.—How can the loss by large clearance be modified? 

Answer.—By early closing of the exhaust and causing compression 
to near the initial pressure. 

Question.—Is the elimination of clearance possible? 

Answer.—No; it is necessary in order to accommodate the lost 
motion in joints and prevent the piston striking the heads. 

Question.—What is meant by working steam expansively? 

Answer.—It is the cutting off the steam-inlet at some definite 
portion of the piston-stroke and completing the stroke by its expansive 
pressure. 

Question.—What is the effect of using steam expansively? 

Answer.—Its effect is in the economy due to the use of the ex¬ 
panding properties of steam below boiler-pressure. 

Question.—To what extent could expansion be used economically 
in non-condensing engines? 

Answer.—The economical nominal expansion can be carried to 
about one-twenty-fifth of the absolute steam-pi essuie. 


410 


THE ENGINEER AND HIS DUTIES 


Question.—To what extent for condensing-engines ? 

Answer.—About one-fourteenth of the absolute steam-pressure. 

Question.—What effect has the clearance on the actual expansion? 

Answer.—The clearance lessens the nominal expansion ratio, so 
that the actual expansion with clearance is less than the nominal 
expansion. 

Question.—How early may a slide-valve cut off? 

Answer.—About five-eighths of the stroke. 

Question.—How can an earlier cut-off be obtained? 

Answer.—By the addition of a riding cut-off valve, which may 
be adjusted for any desired cut-off. 

Question.—How otherwise may a short cut-off be obtained? 

Answer.—In a four-valve engine with one or two eccentrics, and 
in-the Corliss type of engine. 

Question.—How is the speed of slide-valve engines controlled? 

Answer.—Generally by a flyball-governor operating a throttle- 
valve, or by a shaft-governor that varies the throw of the eccentric 
and of the valve. 

Question.—What advantages has a riding cut-off on a slide-valve? 

Answer.—It allows of any desired variation of the speed and 
power of the engine by a great range of the cut-off, and the full value 
of the steam used between its greatest range of pressure and tempera¬ 
ture. 

Question.—What advantages has the drop cut-off in the Corliss 
engine over the riding cut-off in other engines? 

Answer.—It makes a more uniform admission-pressure, a sharper 
head to the expansion-curve, and a better control of the terminal 
exhaust- and compression-pressures. Its peculiar valve-gear allows 
of complete control of the movements of all the valves. 

Question.—What is a condenser, and what its use? 

Answer.—Any application of cold water for reducing steam to 
its primary condition of water and its use in the steam-engine is to 
save the value of its latent heat as a power-economy. • 

Question.—What are the principal types of condensers in use? 

Answer.—The jet-condenser, in which a spray of water comes in 
contact with the exhaust-steam in a chamber; the surface-condenser, 


THE ENGINEER AND HIS DUTIES 


411 


in which the exhaust-steam is condensed on the surface of tubes 
made cold by circulating water; the siphon-condenser, in which the 
exhaust-steam is drawn into and condensed by a single jet of cold 
water under a hydrostatic vacuum made by a water-column about 
34 feet high. 

Question.—What advantage is a condenser to the power-economy 
of a steam-engine? 

Answer.—It will add from 12 to a possible 14 pounds per square 
inch to the mean effective pressure above the atmospheric pressure. 

Question.—What advantage has a surface-condenser over the jet- 
and siphon-condensers ? 

Answer.—It allows all the water of condensation to be used con¬ 
tinually, taking the place of impure water. It is of especial value in 
the marine service and where good water is scarce. 

Question.—Why are high steam-pressures advantageous? 

Answer.—Because of the greater range of temperatures that can 
be utilized for power and their saving in steam by reduced cut-off. 

Question.—What are the objections to the use of high pressures? 

Answer.—They increase the danger of rupture at weak points in 
boilers and pipes, and of shock of moving parts, beside decomposition 
of lubricants, increase of leakage, and larger cost of the power-plant 
to meet increased pressure. 

Question.—How is the economy of a steam-engine expressed? 

Answer.—In the pounds of steam or its water consumed per hour 
per horse-power. 

Question.—Why is it not expressed in pounds of coal? 

Answer.—Because the boiler-duty is independent of the engine- 
duty, and the coal-duty should apply to both boiler and engine. 

Question.—What is superheated steam? 

Answer.—Steam is superheated at any temperature above that of 
the water from which it is generated, or above that of saturated steam. 

Question.—What advantages are attributed to superheat ? 

Answer.—It lessens cylinder-condensation and its waste of power, 
and enables perfect expansion. 

Question.—In what types of steam-engines is it most useful? 

Answer.—In compound and multiple-expansion engines, where the 
loss of steam by condensation is greater than in non-condensing engines. 



412 


THE ENGINEER AND HIS DUTIES 


Question—What may be the possible gain by superheating? 

Answer.—The gain by superheat depends upon the method of 
obtaining it and its amount—in non-condensing engines, from 4 to 10 
per cent.; in condensing-engines, from 6 to 14 per cent.; and in multi- 
expansion engines, from 10 to a possible 20 per cent. 

Question.—What is the use of an indicator? 

Answer.—To show the general conditions of the work of the steam 
by means of the form of the diagram that the recorder makes of 
pressures and volumes. 

Question.—Does a well-proportioned diagram show an economical 
engine ? 

Answer.—Not always; leakages may balance each other and not 
affect the lines of the diagram. 

Question.—What does an ill-proportioned diagram show? 

Answer.—It shows where to look for the faults of the valve- 
motion and its construction, and also the degree of steam-economy. 

Question.—What other important properties does the indicator- 
card show? 

Answer.—A faultless diagram shows the indicated horse-power of 
the engine and the quantity of steam used per horse-power. 

Question.—What is the use of a governor? 

Answer.—To regulate the speed of the engine automatically, by 
varying the volume of steam inversely as the load. 

Question.—What are the principles of action of governors? 

Answer.—The throttling-governor varies the initial pressure, and 
the cut-off governor varies the volume of steam by varying the point 
of cut-off. 

Question.—Which is the more efficient? 

Answer.—The cut-off governor is much the more efficient. 

Question.—What is a “stop motion” attachment to a governor? 

Answer.—A device to stop the steam-supply in case the governor- 
belt breaks, or when the load is too greatly decreased, which over¬ 
speeds the engine. 

Question.—What is lead on a steam-valve? 

Answer.—Lead is the opening slightly of the steam- or exhaust- 
port before the crank reaches the centre. 


413 


THE ENGINEER AND HIS DUTIES 

Question.—How is lead obtained? 

Answer.—By setting the eccentric ahead of the lap-angle; it is 
called the lead-angle on the eccentric. 

Question.—What is lap? 

Answer. It is the extension of the face of the valve over the 
cylinder-ports both ways. Laps are designated as steam-lap and 
exhaust-lap. 

Question—What is the use of lap? 

Answer.—To shorten the period of port-opening from greater 
valve-throw and its quicker motion. 

Question.—How should the eccentric be set for the proper move¬ 
ment of a valve with lap? 

Answer.—By advancing the eccentric, so that the steam-port 
just opens at the moment that the crank is on the centre, which is 
the lap-angle. 

Question.—What effect has exhaust-lap? 

Answer.—It increases compression by retarding exhaust-release 
and possibly choking it. 

Question.—What effect has increase of steam-lap on the cut-off 
and expansion? 

Answer.—It shortens the cut-off and prolongs expansion. 

Question.—How early may a plain slide-valve cut off? 

Answer.—About five-eighths stroke. 

4 

Question.—How short a cut-off may be obtained with a riding 
cut-off ? 

Answer.—From zero to five-eighths and three-fourths in various 
makes of engines. 

Question.—What is the range of cut-off in Corliss engines? 

Answer.—From zero to three-fourths. 

Question.—What is a shifting eccentric? 

Answer.—One that is moved from its centre to its extreme throw 
in a straight line by the varying centrifugal force of a shaft-governor. 

Question.—What is a swinging eccentric ? 

Answer.—An eccentric with an arm pivoted to an arm of the fly¬ 
wheel, and swung in a circular arc from its centre to its extreme throw 
by the varying centrifugal force of a fly-wheel governor. 


414 


THE ENGINEER AND HIS DUTIES 


Question.—What are the advantages of high piston-speed? 

Answer.—It lessens cylinder-condensation and enables greater 
power from lighter engines. 

Question.—What are the disadvantages? 

Answer.—Greater momentum and shock from the moving parts, 
causing increased wear and care in adjustment and lubrication. 

Question.—What is the limit to fly-wheel speed? 

Answer.—Practically according to the material and make-up of 
the wheel. Cast-iron wheels, solid, may have a rim-speed of about 
6,000 feet per minute, although a much higher has been in use. 

For the progressive young engineer there are a thousand or more 
questions which by their answers contribute to his advancement 
and success, and may finally put him at the head of his profession. 

There is plenty of room at the head, and it only requires study and 
practice to reach it. 


ELECTRICAL SEC TIO N 


/ 









The following pages have been prepared for the especial use of 
steam engineers, in order to give them, at a glance, the essence of 
modern electrical practice. A great many new departments of 
electrical engineering have crystallized in the last ten years, and in 
all probability more will assume commercial significance in the 
years to come. 

For this reason, a very brief theoretical treatment has been 
given, in some instances sufficient, it is believed, to indicate the 
trend of future progress. The author knows that the two great 
problems facing the engineer in charge of a steam plant are: First, 
to keep his lights burning; and second, to keep his power supply 
going. In other words, the steam plant and the electrical plant in 
conjunction are used in central station and power-house work for 
lighting, as stated above, and for power purposes. 

To sum the matter up still more explicitly, the power-house 
and central station, or any other case where steam and electricity 
are combined for a common purpose, are merely an instance of 
where electricity of a certain pressure and current is being pro¬ 
duced. Its production, however, necessitates the knowledge and 
observance of certain laws, which absolutely govern the output of 
current. The efficiency of the plant is also a point of direct im¬ 
portance, likewise dependent upon the care and management 
demonstrated by those intrusted with such a responsibility. 

In the following pages of text, in which the reader will find a 
variety of subjects treated, of direct interest to the engineer, the 
author believes information is being given in a terse and useful 
form for immediate use, especially in conjunction with the questions 
and answers appended. 

A great deal of ground has been covered in these pages, and a 

great deal of information necessarily presented, with adequate 

explanations under the circumstances. The point kept in mind 

throughout by the author, however, was this: that the engineer is 

417 


418 


PREFACE 


a busy man, and prefers information and such principles as are by 
nature part of the facts, given in a simple and comprehensive 
manner. Lengthy explanations composing part of highly complex 
analyses would hardly be the thing in any case. Therefore, 
fundamental principles and what might be called fundamental facts 
compose the structure of the text. The troubles apt to arise in a 
piece of active machinery are of more direct importance to the 
steam engineer than involved theories. Some of the most im¬ 
portant of these have been given consideration in connection with 
the parts of a dynamo or motor. Lighting in its various forms 
has also been reviewed and the salient and practical features of 
each given distinct attention. 

On the whole, the engineer will be readily able to test the value 
of the information given, by utilizing it when the time comes. 
It is the author’s belief that it will prove to be of great service, not 
only at a critical time, but as a means of presenting a bird’s-ej r e 
view of what can be called modern electrical practice. 

Newton Harrison. 

November, 1906 . 


THE DYNAMO 


OPERATION OF THE DYNAMO 


The operation of the dynamo maybe best and most briefly described 
as that of the movement of conductors with respect to lines of force, 
or of lines of force with respect to conductors. By this is meant 
that in the ordinary type of direct- or alternating-current generator 
this idea (Fig. 1) predominates: namely, the movement or cutting 
of lines of magnetic force with respect to conductors, or the converse. 



' \ 
i ' 

MOVEMENT OF CONDUCTOR 



MOVEMENT OF MAGNET 


Fig. 1.—Effect of moving the conductor or the magnet. 


It is evident from this statement that there are two kinds of genera¬ 
tors: the direct and the alternating current. It is readily realized that 
differences must exist between one and the other type, distinguishing 
them in such a manner that they stand apart, as it were, representative 
of two systems. These differences, which are the means by which 
one kind of current is known from the other, are fundamental. Tin 1 
direct current is one which is unvarying or unchangeable (Fig. 2) in 
its direction. The alternating current is one which is constantly 
varying or changing its direction, the construction ot geneiatois, and 
to some extent their operation, are based upon the kind of current 
they generate, and the service that particular current performs. 
















420 


THE DYNAMO 


The operation of the dynamo in general, therefore, represents either 
the movement of the conductors or the magnetic field relatively in 



Fig. 2.—The tremor in a direct, and the reversals in an alternating current. 


such a manner that by means of a commutator (Fig. 3) or collector- 
rings, or by dispensing with either, electricity is produced of the char¬ 
acter of a direct or alternating current. As a general rule, in direct- 



Use of commutator converts al¬ 
ternations into a direct 
current. 

Fig. 



Use of collector-rings permits 
the natural alternations 
to pass outside. 


current generators the source of magnetism or the field remains at 
rest. The armature with its conductors is set into rotation. In 
this case the conductors are made to cut the lines of force and generate 
electromotive force. 


GENERATING ELECTROMOTIVE FORCE 

A dynamo or motor is simply a generator of electromotive force. 
The electromotive force produced by the dynamo is utilized for lighting 
or power purposes. The electromotive force produced by a motor 
serves to regulate its current-supply, by acting automatically and 
oppositely to the pressure sending current in. The electromotive 








THE DYNAMO 


421 


force of a dynamo is calculated and developed with respect to the 
kind of work it is to perform. For instance, it will be 115 volts for 
incandescent lighting, or 500 volts for trolley-lines. The electro¬ 
motive force is generated within the conductors when they cut the 
lines of force. 

The basis ot all theoretical and practical calculations is that a 
volt is produced if lines of force are cut by a conductor at the rate of 
100,000,000 a second. When the elements of revolutions per sec¬ 


ond, conductors, and lines of force are considered together, they 
may be conveniently arranged as follows: 

Volts = lines of force X revolutions per second X conductors on the 
armature -h 100,000,000. 

Calling the volts E, the lines of force N, the revolutions per second 
S, and the conductors C, the formula may be written: 


E = N xSxC-f-100,000,000. 

For instance, if it is desirable to generate 115 volts, the field N 
may equal 5,000,000 lines of force (Fig. 4), the conductors C may 


CONDUCTORS=100 



Fig. 4.—Field, speed, and conductors producing 115 volts. 


equal 100, and the speed S may be 23 per second. On this basis the 
formula gives: 

115 volts = 5,000,000 X100 X23 -4-100,000,000. 

All the different types of generators are constructed on this prin¬ 
ciple as a foundation. Whatever variations in appearance occur, 
they cannot be regarded as other than differences due to the various 
applications to which generators are put. 














422 


THE DYNAMO 


USE OF THE COMMUTATOR 


Beginning with the generation of the electromotive force, it re¬ 
mains to be seen how the direction of the current is affected by it. 
It may be stated that the movement of a conductor past a magnetic 
north and south pole has the effect of not only generating electro¬ 
motive force, but giving it direction, so to speak. By this is meant 
that a copper wire moved past a N pole will have a current pass 
through it in an opposite direction to a wire similarly moved past 

a S pole. Both may pro¬ 
duce exactly the same elec¬ 
tromotive force, but the 
direction of the current the 
electromotive force sets into 
action will be opposite in 
one case as compared with 
the other. 

A generator-field consists 
of two or more magnetic 
poles arranged alternately. 
The north and south poles 
follow each other respec¬ 
tively. Therefore a conduc- 

Fig. 5. —Currents under N poles flowing out- ^°1 produce an electlO- 
ward. Currents under S poles flowing inward. motive force tending to send 



a current in opposite direc¬ 
tions as it passes a N pole and then a S pole. There are many 
conductors on the armature of a direct-current generator. Conduc* 
tors passing S poles will all carry a current in the same direction. 
Conductors passing N poles will all carry a current in an opposite 
direction (Fig. 5) to those passing the S poles. 

The problem of successfully directing these two opposite but si¬ 
multaneous flows of current into a circuit commonly called a direct- 
current circuit is solved by means of a commutator and brushes. The 
function therefore of a commutator is to conduct all electricity of one 
direction into one brush or set of brushes, and all electricity of an 
opposite direction into another brush or set of brushes. By this 


THE DYNAMO 


423 


means the naturally alternating current generated in the armature- 
conductors of a direct-current machine is rectified or commutated. 


REGULATING THE DYNAMO 

• t» 

That which constitutes the regulation of a dynamo is accomplished 
by means of the field in the case of a direct-current incandescent- 
light shunt-wound machine. The field is either increased or decreased 
in strength, this being the means by which the electromotive force 
of the armature is raised or lowered. In other words, the fact that 
the armature rotates in a magnetic field of more or less lines of force 
is an evidence of the generation of a correspondingly higher or lower 
electromotive force. For instance, if 115 volts are obtained by 
means of 5,000,000 lines of force in the field, acting upon 100 armature- 



Fig. g.—Effect of resistance in increasing and weakening the field strength and the 

electromotive force. 

conductors rotating at a speed of 23 revolutions a second, an increase 
or decrease in the number of lines of force would mean in proportion 
just the same change in the volts generated. 

If the 5,000,000 lines of force are increased to 6,000,000 or lowered 
to 4,000,000, the volts produced (Fig. 6) would be increased to 138 
or lowered to 98. In other words, by causing a \aiiation in the 


























424 


THE DYNAMO 


strength of field by varying the current in the field-coils, a degree of 
effective regulation is obtained which has become established in 
common practice in connection with what are called shunt-wound^ 
dynamos. 


CLASSIFICATION OF DYNAMOS 

Dynamos are classified under two general headings: first, direct- 
current generators; secondly, alternating-current generators. The 
direct-current generators are further subdivided (Fig. 7) into series- 
wound machines, shunt-wound machines, and compound-wound 
machines. The alternating-current, generators are classified with 





LAMPS IN MULTIPLE 


Fig. 7.—Three types of direct-current generators. 


respect to the character of the current they develop. On this basis 
it may be said that there are single-phase machines, two-phase 
machines, and three-phase machines. 

Among alternating-current generators are found forms of construc¬ 
tion of a special character, in which neither the armature-wire nor 
field-wire is moved when electromotive force is being produced. An 
essential element of alternating-current practice is the transformer, 
by means of which the voltage is raised or lowered for transmitting 
or distributing the current. 




































THE DYNAMO 


425 


REGULATION WITH A SERIES -WOUND 

DYNAMO 

The series-wound dynamo is generally employed for a system of 
electric lighting in which a constant current is- necessary, such as 
high-tension arc-lighting, for instance. The function of this type of 
generator is to provide a current of 10 or 12 amperes and a voltage 
that is capable of being adjusted by special means to suit the number 
of lamps in use. The arc-lamps are connected in series, each lamp 
taking the same number of volts. If twenty or thirty lamps are thus 
connected, twenty or thirty times the volts required for one lamp is 
necessary. Allowing 50 volts as the amount required for each lamp, 
the total voltage to be generated would equal 20X50 or 30x50, or 
from 1,000 to 1,500 volts. 

Arc-lamps as now used may be of the open or closed arc type. 
By this is meant that the carbons either burn in the open air, lasting 
only about eight or ten hours, or are enclosed in a small globe. Each 
lamp takes 50 volts if of the open air type. If of the closed globe 
type each lamp will take about 80 volts. The dynamo must 
be able to automatically raise or lower its voltage when lamps are 
turned on or off. When more lamps are added to the line, more volts 
will be required; in fact, as much more as there are extra lamps. 

When lamps are cut out, less volts will be required, in proportion to 
the number of lamps. For instance, if ten lamps of the closed globe 
type are added to the circuit of a series-wound dynamo, by simply 
turning them on, 10x80, or 800 volts more must be sent into the 
.line. On the other hand, if ten lamps are cut out, 800 volts less in 
the line will do. Fewer lamps turned on or off would mean the same 
thing—more or less volts accordingly. The series-wound dynamo, 
with an automatically varying voltage as described, but a constant 
current, meets these requirements by shifting its brushes (Fig. 8) 
automatically around its commutator. This is based upon the prin¬ 
ciple that between two given points on the commutator the generator 
gives.out its highest and its lowest voltage. If the brushes can be 
made, by means of the attraction of an electromagnet, to move to 
such points of the commutator that these points will supply just the 
volts required by the number of lamps in use, the problem is e^ identl} 

solved. 


426 


THE DYNAMO 


The actuating magnet which causes this regulation is also in 
series with the line, and is sensitive to the current in the line. If for 
an instant that current is too high, the power of the magnet is sufficient¬ 
ly increased to move the brushes over to a point where the pressure 
drops. If the current in the line is too weak, the power of the magnet 
reduces sufficiently to permit the brushes to assume a new position 

r COIL WHICH CHANGES THE POSITION OF 
THE BRUSHES ON THE COMMUTATOR 





on the commutator, where more volts may be sent out over the line. 
This adjustment is continually going on in a series arc-light machine 
of modern construction. Though other methods of regulating the 
voltage and keeping the current constant have been tried, this method 
has been generally accepted and adopted as the best to be used under 
the circumstances involved. 

REGULATION WITH A SHUNT-WOUND DYNAMO 

The shunt-wound dynamo is one in which the fields take but a 
small percentage of the total current. In large generators the fields 
take from 1 to 2 per cent., or even less. In small generators the field- 
current will represent a heavier percentage of the total armature- 
current. In practice a resistance is inserted in the field-circuit, so 
that its manipulation will control the amount of current passing into 
the field-winding. When a shunt dynamo is being loaded up, the ten- 


















THE DYNAMO 427 

dency of the lamps to drop in candle-power becomes more and more 
apparent. 

The causes operating to bring about this effect are found 
(Fig. 9) in the machine as follows: First, drop in the armature-con¬ 
ductors due to the armature-current passing through the armature- 
resistance, represented by CxR; secondly, demagnetizing-field of the 
armature, through which the influence of the armature as an electro¬ 
magnet opposing the field proper becomes more and more magnified. 
These disturbing influences may be readily understood as acting as 
means of cutting down the volts obtainable from the generator to a 
marked degree, unless an effective remedy is employed. 

It is evident that the volts lost in the armature, through drop of 
potential, can only be compensated for by generating that number * 
of volts extra. It is also evident that the reactive magnetic effect 
of the armature can only be compensated for by providing as many 
more lines of force, or as much more magnetism, as has been ren¬ 
dered ineffective by it. In other words, the only way to regain the 
volts actually lost in the armature, and those additional volts which 


REACTIVE FIELD 



Fig. 9 > —Armature-reaction and armature-drop in a shunt-wound dynamo. 

would be generated in it were some of the power of the field not 
destroyed, is by supplying enough extra lines of force when required 

to meet this emergency. 

For this reason, therefore, the rheostat inserted in the field-circuit is 
so utilized that when the dynamo is running with a light load, little 
or no current passes through it. When the load is increased, the 
rheostat is so adjusted that the field-windings take moie cunent. 
Cognizance of the candle-power of what is called the pilot-lamp, or 
of the pressure indicated by the voltmeter, will enable the attendant 









428 


THE DYNAMO 


to move the rheostat to the proper point. This is not an automatic 
system of regulation, because of the constant observation required of 
the attendant. Automatic preservation of the normal or working- 
lamp pressure is obtained by means of the compound-wound gen¬ 
erator. 


REGULATION WITH A COMPOUND-WOUND DYNAMO 

Preserving the pressure automatically by means of a compound 
winding, simply means the employment of a winding, or rather of 
two windings, one of which is simply a shunt winding, and the other a 
series winding. In other words, the advantages of both are combined 
in such a manner that when the generator is called upon for more 
current, it provides it without any external signs of a drop of pressure. 


SHUNT WINDING 



Fig. 10.—Series winding produces lines of.force that equal those the armature 

destroys. 


Through this means, at a low point of load, the lamps are not too bright , 
or at a high point of load too dim. The general principle involved 
is that of sending through a few turns of heavy wire (Fig. 10) wound 
around the field all the current the dynamo generates. In this 
manner the more current the dynamo produces the stronger it makes 
its field in consequence. 

When there is little or no current coming from the armature, 































THE DYNAMO 


429 


the field is only that produced by the shunt winding. Where there 
is a heavy current produced by the armature, not only is the shunt 
winding supplying its quota of magnetism to the field, but its effect 
is augmented to the extent of the magnetism supplied by the few 
turns carrying the total current, commonly called the series-turns, 
in contradistinction to the shunt-turns. Magnetism is therefore 
produced in the compound-wound machine by two sets of coils whose 
effects are cooperative. The shunt winding in such a case does not 
differ in character or principle from that of an ordinary shunt-machine. 
The series or compensating winding is there for the purpose of adding 
as much additional magnetism to the field as is required to compensate 
for the armature-reaction, and of supplying as many extra volts to 
be generated as will make up for those lost by drop. 

For instance, if the shunt-field supplies 5,000,000 lines of force, 
and the armature at no load gives 115 volts, the machine at full 
load, without the series-coil, may have an effective field of only 
4,000,000 lines of force and give only 95 volts. This would mean very 
bad lighting and a great waste of power. The series-coil therefore 
adds enough extra magnetism to build the field up to, and keep it 
constant at, a little over 5,000,000 lines of force. A little over 
5,000,000 lines of force are necessary, because there is armature-drop 
as well as field-reaction to compensate for. Thus, in a case where 
the volts drop at full load, from the initial pressure of 115 to 95, the 
weakened field may account for 15 or IS volts, and the armatuie-di op 
for about 2. There is a little drop as well in the series winding itself 
to allow for, and the switchboard and the heavy mains leading there¬ 
to are not to be forgotten in including all possible sources of loss of 
pressure in the machine and the points of distribution of its power. 


CHAPTER XXV 


Testing 

TESTING A DYNAMO FOR FAULTS 

A dynamo may be tested for faults such as are usually denominated 
grounds, short circuits, sparking, or failure to generate, etc. It is 
best to treat of these conditions categorically, in order that each may 
appear in its true aspect. If the field-coils are grounded, due to 
moisture, poor insulation, or the actual contact of copper to iron, 
two cases are presented: first, a ground in one coil; secondly, a ground 
in both coils. Heat is the phenomenon which always presents itself 
in one or more coils due to these causes. If one coil becomes heated 

to a much greater extent than 
the other, the cool coil is 
either severely grounded or 
short-circuited. 

The ground may have oc¬ 
curred at either the beginning 
or the end of the coil. If at 
the beginning, the coil will be 
cooler than if it had occurred 
at the end. By this is meant 
(Fig. 11) that if sufficient 
length of the coil carries the 
current, it will be warmer 
than if it only passed through a short length and then entered the 
other coil. The cooler coil, on the other hand, may be in contact 
with the iron or itself at two places. In such a case it will be short- 
circuited, by which is meant that a greater or a lesser part of the 
winding is cut out. 

If a greater or a lesser part of the winding of one coil is not in 

circuit, the current does not meet with the same resistance, but with 

less, and in consequence the second coil is carrying too much current 
430 



Fig. 11.—Wire touching iron, and wire 
touching wire. 














TESTING 


431 


as well as part of the first coil. For two coil-fields this is true, though 
the same principle of locating the cooler coil or coils, where more 
than two coils are in series, will enable the attendant to draw conclu¬ 
sions as to the ground or short circuit for purposes of repair. Baking 
a coil to dispel moisture is often a means of ..eradicating latent faults of 
this character. 


sparking 

Sparking may be caused by too great a load on the dynamo, or by 
a wrong position of the brushes. One brush may not be diametrically 
opposite the other in a two-pole machine, or the brushes may not 
be properly adjusted on the commutator if they belong to a multipolar 
machine. If a four-pole machine, they 
should be 90 degrees apart, if a six-pole 
machine, 60 degrees apart, etc. The 
simplest method of getting the correct 
distance between brushes is to count 
the commutator-bars and divide them 
numerically by the number of poles of 
the generator. Sometimes the cause 
of sparking is mechanical, by which 
is meant that the bars may be loose, or either the bars or the mica, 
or both, project beyond the commutator in general. The difficulty 
is frequently found (Fig. 12) in the more rapid wearing away of the 
copper bars before the mica itself has worn down. 

The mica is a mineral product of a greater hardness than might 
have been expected, and in consequence the friction of the brushes 
affects it the least. Sandpapering the commutator is of little or no 
use. The only effective remedy is that of turning down the commu¬ 
tator—a thing best done by a lathe or by a special commutator 
turning device found on the market. The brushes may not be of the 
proper quality, and thus cause sparking. For instance, as a matter 
of information it may be stated that carbon brushes will not do in 
all cases. Carbon brushes are best suited to hard-drawn copper bars, 
not to soft ones. Segments of a less durable material will only be 
ground away in a fine powder, whose ultimate injury to the machine 
will be greater the longer this condition exists. In addition it may be 
stated that hard or soft carbon brushes may work with different 



Fig. 12.—Mica wearing away 
slower than the bar. 



432 


TESTING 


degrees of efficacy, according to the type of machine and the nature 
of the design. 

There is such a thing as ineradicable sparking, due to bad design. 

In such a case as this little can be done bv those intrusted with the 

%/ 

operation of the machine. Sparking is sometimes caused by a too 
small air-gap between the armature and the field. As previously 
stated, it may be due to a too great overload of the machine. There 


are features involved in the design of a sparkless machine which bring 
into close relation the arc of embrace of the pole-piece, the length of 
the air-gap, the ampere-stream under each pole, and the magnetic 
spray from the pole-piece. The position of the brushes, which gives 
what is called sparkless commutation, is largely controlled by the 

existence of a magnetic fringe which extends 
beyond the leading pole-tip. 

The state of this fringe indicates, in certain 
respects, a measure of the amount of spark- 
lessness possible to achieve. The adjustment 
of the brushes is made for the purpose of 
securing a point on the commutator where 
the reversal of current in the successive 
armature-coils passing under the brush or 
brushes is accomplished without sparking. 
This magnetic fringe or spray is effective in 
reducing inductive effects in the coil or coils 
undergoing reversal, by introducing an op¬ 
posite influence. Therefore the bad effects of 
reversal when the brush short-circuits the 
coil (Fig. 13) and the influence of the fringe 
counteract each other if the design of the machine is correct in these 
details. Sparking is therefore generally inherent, though sometimes 
due to the causes noted under the head of mechanical defects, or to a 
lack of judgment in selecting a suitable brush for the generator. 



Fig. 13.—Time at which 
pole-piece spray is useful. 


DYNAMO FAILS TO GENERATE 

The development of electromotive force is the primary and essen¬ 
tial feature of a dynamo’s operation. If the machine will not “pick 
up,” that is to say, begin to generate its electromotive force, there 










TESTING 


433 


ai e cgi tain possibilities causing this condition, which may be enumer¬ 
ated as follows: The residual magnetism may be absent, in which case 
it must be restored by means of a current sent into the field-coils 
m the right direction. The magnetic poles of the machine may be 
the same (Fig. 14), in which 
case the connections must be 
changed. The fielcl-coils may 
have an open circuit, in which 
case they must be tested, and 
the coil or coils repaired. 

A more scientific reason 
than these may account for 
the inability of a dynamo to 
generate electromotive force 
by referring to its shunt-resist¬ 
ance and speed. In other 
words, the simple fact of the 
matter is this: that if the speed 
of the armature is not suited 

to the resistance of the shunt, due to this said resistance being too 
great, the machine will not generate. There is what is called a criti¬ 
cal speed for shunt- or compound-wound dynamos, below or above 
which normal conditions will not exist. 

If the generator or its outgoing circuits have made a double ground, 
the equivalent of a short circuit, the dynamo will not generate. A 
test of the circuits is therefore a necessary prelude to investigations 
of this character. Faults in the armature itself may be found in the 
nature of short circuits of one or more coils, which coils will get very 
hot on running the machine, this condition preventing any consider¬ 
able outside pressure from appearing. A broken coil, on the other 
hand, causes sparking and the blackening of the bars between the 
ends of the break. 



Fig. 14.—Case in which the poles are alike. 


CAUSE OF HEAT IN THE ARMATURE 

The existence of heat in the armature may be due to a variety of 
contributing influences. The dynamo may be overloaded, or the 
heat may issue or be conducted from some other source than the 


434 


TESTING 


armature itself. There may be difficulties present in the coils, such as, 
for instance, short circuits. The armature may be filled with dampness 
and generally grounded, a condition removed only by means of a bak¬ 
ing process. Certain coils may be so wound that they do not send their 
currents in the proper direction. If the winding is reversed, a form 
of parasitical current of large amperage develops, causing great heat. 

A source of disturbance and heat is discovered in the use of very 
thick copper wires or bars. The effect of these is a little extraordinary 


in the sense that they may 
develop currents within 
themselves strictly para¬ 
sitical in nature. The 
thick bars may have ed¬ 
dies of electricity (Fig. 15) 
flowing in them, of such 
strength that they become 
intensely hot. These ed¬ 
dies are due to the fact 



Fig. 15.—A copper bar with parasitical currents. 


that one-half of the bar longitudinally is developing electromotive 
force, while the other half is not. 



as it is entering under a pole-edge a little sooner than the other half, 
simply on account of its extreme width or thickness. The brushes 
may be in the wrong position, on the other hand, and give rise to 
heating, or two commutator-bars or a commutator-bar and the frame 
or bushing may touch together. In running a generator the signs of 
excessive heating must be carefully watched for; otherwise the fact 
will be heralded in the way of a smell of burning insulation at a time 
when the need of light and power is of vital consequence. 

HEAT IN THE COMMUTATOR AND BRUSHES 

Too much friction (Fig. 16) between the commutator and brushes 
is a prolific cause of heat. Yet the contrary is true, that when the 
contact between them is insufficient, heat is developed due to the 
passage of the current through a comparatively high resistance. 
The heat generated by means of an electric current is measured in 
watts by squaring the current and multiplying by the resistance. 





TESTING 


435 


For instance, if 10 amperes are passing through a resistance of 10 ohms, 
according to the law governing such cases, the watts wasted will 
equal 10x10, the current squared, multiplied by 10, the ohms’ resist¬ 
ance, or 100 x 10 = 1,000 watts. The heating effect is therefore 
measurable by the waste of watts on this basis. And the heat devel¬ 
oped may be also noted to be proportional to the square of the current 
in amperes. 

By this is meant that if the 10 amperes are doubled, the watts 
will be quadrupled. If the 10 amperes are made 20, the watts 
wasted become 20x20x10=4,000 watts instead of 1,000. In other 
words, the effect of twice the current, from the heat standpoint, is to 
multiply the heat four times. The effect of three times the current 
would be to multiply the heat nine times, if the resistance remains 
the same. 

Where commutator and brushes are concerned or any conduct¬ 
ing part carrying a very large current, the least resistance may 
mean a very large amount of wasted power. The brush may press 



Fig. 16.—Temperature of commutator affected by brush pressure 


properly, but may have too great a resistance and develop heat, 
or the casing holding it may not make the proper contact and cause 
heat to manifest itself. An ordinarily good contact will prove to be 
very deficient in any case where a very heavy current passes through 
it, as just indicated. 


RADIATING SURFACE OF COILS AND CURRENT- 

CARRYING PARTS 

In order to present with adequacy the subject of heat in the various 
parts of an electrical machine, it is necessary to touch upon the physical 
or geometrical facts (Fig. 17) concerning the rise of temperature 
















436 


TESTING 


in conductors, coils, armatures, commutators, and brushes. As fai 
as the geometrical facts are concerned, it may be said that the laiger 
the surface of a heated body the more rapidly it cools. The conveise 


is also true, that the smaller 
the surface of a heated body 
the hotter it becomes. From 



the standpoint of physics, 
however, temperature is mere¬ 
ly an indication, so to speak, 
of the degree of concentration 
of the heat. 



By this is meant that with 
a given quantity of heat, say 
that given out by a candle- 
flame for an hour, a.mass of 
material with a large surface 
would not show a high tem¬ 
perature. A small mass of ma¬ 
terial, however, would show a 


WATTS 


WASTED 200 


Fig. 17.—Effect of radiating surface on tem¬ 
perature with the same waste of energy. 


very high temperature, particularly if its surface was very small. 
From this standpoint, therefore, temperature is dependent upon not 
only the amount of heat actually present, but the rate at which it 
is being radiated. In this sense a conductor carrying electricity and 


developing heat will rise in temperature according to the amount of 


metal it represents in proportion to its outer radiating surface. 

Coils carrying electrical energy, such as field- or armature-wind¬ 
ings, or commutators or brushes, must be provided with sufficient 
surface for radiation to get rid of the heat quickly enough to pre¬ 
vent any but a limited rise of temperature. In steam-engineering 
the general problem is such that it is a matter of economy to retain 
the heat as far as possible. In electrical engineering the process is gen¬ 
erally reversed. Getting rid of the heat as quickly as possible is a feat¬ 
ure of daily practice. 


TYPES OF MOTORS IN SERVICE 


The types of motors in service are best classified under the titles 
of series, shunt, and compound or differentially wound machines. 
The series motor is one in which the speed rises to a destructive point 













TESTING 


437' 


without a load or curb. The shunt motor is one in which it is necessary 


to have a resistance in series with the armature when starting it up. 


The compound or differentially wound motor is one in which the 
series winding acts either to increase-the speed of the motor, or to 
increase its pull or torque with a heavy load. The reason why the 
series winding acts this way is simply because with one method of 
connecting its terminals the field is cut down. By reversing the con¬ 
nections (Fig. 18) the field is built up. In a shunt motor the weakening 
of the field means a higher speed. The strengthening of the field 
means a greater pull and a lower speed. 

Armature-coils may be burned out or grounded, or the field may 
be deficient in the motors whose types are given. A general prin¬ 
ciple of great value in re¬ 
lation to the speed and 
pull, with respect to the 
practical application of 
direct-current motors, is 
that the field-strength and 
armature-current are the 
dominating factors. As a 
general rule, the greater 
the armature-current and 
the strength of field, the 
greater the pulling power 
of the machine. 

There is such a condi¬ 
tion inviting danger to the 
motor as too low a speed. 

A shunt-, series-, or com¬ 
pound-wound motor too 
heavily loaded will natur¬ 
ally carry too much cur¬ 
rent, heat too much, run too slow, and probably spark too much in 
service. A shunt- or compound-wound motor running too fast is a 
case (Fig. 19) in which the field is dangerously weak. The shunt-coils 
in such a case should be carefully examined, and the series-coils 

reversed in connections. 

A principle enunciated by Jacobi many years ago relates to the 


V 


v 




SHUNT WINDING 


SERIES WINDING 







Fig. 18.—Both.series and shunt winding acting to 
increase the strength of the field. 










438 


TESTING 


maximum torque of the armature in about the following terms: A 
motor is doing its maximum work when it is loaded to such a point 
that its speed has become one-half the normal value. In other words, 
the heavy loading of a motor may be effective in producing a surplus 
of power, but this is only done at the sacrifice of efficiency. The over- 



Fig. 19.—A shtmt- or compound-wound motor with no field. 


loading of a motor therefore to the point noted, namely, half the speed, 
means a theoretical efficiency of only 50 per cent, and a practical 
efficiency of even less. The average motor-efficiency cannot be given 
in exact figures except for a given size and type, but it may be stated 
on good authority that it is over 80 per cent, and less than 95 per cent. 

As regards the armature-coils being burned out or grounded, or 
the field-coils exhibiting deficiencies, it may be said that the first 
case will be manifest in the shape of an unusually heavy current 
with probable fuse-blowing or circuit-breaker action; the second will 
be in evidence in the form of a weak magnetic field with phenomena 
as noted in the way of high speed above the usual value. 

SPARKING IN THE MOTOR 

The presence of a very high speed, and a line of sparks around the 
commutator, with two of the bars deteriorated and burned, means 
a case of open circuit in the armature-winding. When one of the 
coils or both are out of order, so that little or no field is present, the 
armature will spark badly if turned by hand with resistance in circuit. 























TESTING 


439 


The field-windings may be opposed to each other, and in this case 
the armature will tear itself to pieces if run idle without a preliminary 
examination ol some sort. The rules which seem to be best to observe 
in connection with shunt- and compound-wound motors is to see that 
the starting resistance is in series with the armature when it is started, 
and that the field is on before current enters the armature. 


THE BACK ELECTROMOTIVE FORCE OF A MOTOR 


The back electromotive force of a motor is best understood as due 
to the rotation of the armature-conductors in the magnetic field. 
Through this, electromotive force is generated which has a polarity 
opposed to that of the entering pressure. To distinguish one from 
the other, the line-pressure is called the impressed electromotive force 
(Fig. 20), and the armature-pressure the back or counter electromotive 
force. The exact value of the back electromotive force may be cal¬ 
culated by means of the current and the armature-resistance. 

If the current in the armature at any point of load is multiplied 
by its resistance and the product subtracted from the impressed 
electromotive force, the difference is the back electromotive force. 




.THE IMPRESSED 
E.M.F. 


DIRECTION 

OF THE BACK E.M.F. 






-<r 


Fig. 20.—Opposition of the back to the impressed E. M. F. in a motor. 


For instance, If the armature-resistance • is .1 of an ohm, and the 
armature-current 50 amperes, the product is .1X50 = 5 volts; sub¬ 
tracting this from an impressed electromotive force of 250 volts would 
give a back electromotive force of 250—5 = 245 volts. 

Electrical efficiency is obtained by dividing the 245 volts, back 
electromotive force, by the 250 volts, impressed electromotive force, 
or 245-e 250 =98 per cent. But the electrical efficiency is not the 
one distinguished by the title “ commercial efficiency. This last 
efficiency is ecjual to the ratio between the output and the input, oi, 











440 


TESTING 


in other words, it may be stated that the commercial efficiency is equal 
to the power taken out divided by the power sent in. 


HUMMING AND OTHER NOISES IN MOTORS 

Humming and other noises are associated to a very marked extent 
with motors in operation. What is commonly called humming is 
found in motors in which the armature-slots carrying the conductors 

are not properly related to 


POLE TIP 



LINES OF FORCE SNAPPING 


ARMATURE 


Fig. 21.—Cause of hum between pole-tip 
and slotted armature. 


the pole-tips of the machine. 
There is a certain snap when 
the armature-tooth (Fig. 21) 
leaves the pole-tip. The effect 
of this magnetic snap is to set 
up a molecular vibration in 
the pole, which is sometimes 
greatly augmented by favor¬ 
able acoustic conditions. The other sounds may be regarded as due to 
a vibration of the brushes with respect to the commutator of the motor. 

A peculiar chattering, as it is called in the machine-shop, is due 
to the lack of proper inclination of the brush or brushes to the com¬ 
mutator. The commutator, on the other hand, may be rough and 
require turning down. A method of localizing the sound is to lift the 
brushes off the machine when running idle. In this manner it is 
possible to ascertain whether the noise is an accentuated hum due to 
the armature-teeth or the commutator and brushes. A little oil or 
vaseline is frequently efficacious in this respect. It is good practice 
to hie the brush carefully to the proper angle to remedy this evil. 

Another salient cause of vibration and noise, however, is the lack 
of balance in the armature itself. It is a common practice, after a 
motor or dynamo-armature has been completed, to test it for mechan¬ 
ical balance on knife-edges. It is sometimes done so hastily or care¬ 
lessly that the balance is imperfect. This can be readily discovered 
in the running machine by means of the hand when placed upon it. 
There is always a possibility, however, that the pulley may be defec¬ 
tive. In this case it should be removed and carefully turned down 
until balanced. Removal of such disturbances better insures the 
period of usefulness of the machine. 



CHAPTER XXVI 


THE SWITCHBOARD 

That which is typified by the name of switchboard in connection 
with central stations, power-houses, or private installations, is simply 
a convenient centre from which or to which all important conductors 
are led (Fig. 22), and at which the instruments and protective 
apparatus may be found. The switchboard is generally made of slate 
or marble, and of sufficient size to contain on its polished surface not 
only the terminals of circuits, but a variety of unique but never¬ 
theless indispensable adjuncts of the equipment. It is necessary 
to classify the elements constituting the direct-current switchboard 



Fig. 22.—Circuits connecting to switchboard. 


equipment in order to form an adequate idea of its importance and 
serviceability. This classification would assume the following form: 

1. Measuring-instruments, by which would be included those em¬ 
ployed for the measurement of volts, amperes, and watts. 

2. Controlling devices, by which would be included all switches 
controlling main, feeder, and subsidiary circuits. 

3 Protective devices, by which would be included all fuses, cut- 

441 


































442 


THE SWITCHBOARD 


outs, and circuit-breakers of all kinds or shapes and embracing within 
that scope lightning-arresters as well. 

4. Regulating devices, under which heading the rheostats in the 
fields or shunt-circuits and the bus-bars would be consistently in¬ 
cluded for this purpose. 

5. Testing devices, under which heading would be included ground- 
detectors and such additional instruments as may be used to serve 
the same purpose, and may therefore be regarded as switchboard 
accessories. 

The classification of the wires is part of the same proposition, 
for it is evident that the original purpose of the switchboard was only 
to coordinate or centralize the most important wires. For this reason 
the circuits may be regarded as belonging to one or the other of such 
divisions as the entire classification of the switchboard may include. 

CLASSIFICATION OF CIRCUITS 

The natural arrangement of conductors would be in the order of 
their essentiality or importance. For this reason the wires from the 
dynamo come first and are called mains. The wires from the mains 
are generally employed as supply-wires or feeders (Fig. 23) to the dis- 


FEEDERS 



tributing-wires with which they are connected. The feeder-wires 
supply current to the branches, and by means of the more important 
or heavier branch wires connect a class of sub-branches or subsidiary 


































THE SWITCHBOARD 


443 

circuits. On this basis there appear (1) mains, or wires from the 
generator; (2) feeders, or wires from the switchboard; (3) branches 
of a heavier character supplied by the feeders; and (4) sub-branches, 
or final distributing-wires. 


»» 

CENTRES OF DISTRIBUTION 

The switchboard carries the devices which exercise the various 
influences noted over the whole system. There are, however, points 
on each floor, or group of floors or rooms, in which a secondary 
influence may be exercised. Such points are called “ centres of dis- 


BRANCH 


OR 


FEEDER 


co 

LJ 


I 

o 


< 

£E 

CD 


cc 

O 


co 

LI 

X 

o 


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cc 

CD 


CD 

D 

co 


r\ 1 r\ rs 


rs rs i r\ r\ 

V-T—VJ ■"J 

V 

p\ r\ r\ 

O" 'vJ.1 u u 

J 

CJ "U I u- u 

a /m r\ r\ 

r\ p\ 

V. 



J 

p> r\ f r\ r\ 

u— \j mi ■ 

no o o 

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r KJ V u 

p\ r\ r\ 

^r- KS mmm {J v 

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V—v D U 

r\ Pi r\_ . 

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PN r\ J Py O 

p, pv I p>. 

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O—^ {J - o 

p» o ^ 

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o o o . 

CIRCUIT CONTROLLINgC 
SWITCHES 

( 

J 

) C 

1 

FUSES - ^ 

) 


CO 

LJ 

X 

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z 

< 

cc 

CD 

CC 

o 


X 

o 

z 

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CO 


Fig. 24.—Use of a panel board at a center of distribution. 


tribution.” They appear in the form of miniature switchboards 
(Fig. 24) which are devoid of other than controlling and protective 
appliances, namely, switches and fuses. 

The feeders enter these panel boards, as they are called, and from 
them various branches radiate to the groups of lights receiving the 
current. All important branches connect with the feeder through the 
medium of a switch and fuse. The sub-branches may or may not 
be provided with these, depending upon the character of the lighting; 
but the entire system of wires on this basis, from the generator to 
the lights, is adequately protected against overflows of current. 





































































444 


THE SWITCHBOARD 


S W I T C II B O A It I) APPLIANCE S 


The switchboard, as an entity, is itself subdivided, according 
to the purpose its different sections serve. These sections are now 
made in distinct panels (Fig. 25) or part-switchboards, according 
to the following system: 

(1) The generating-panel, with which the generator connects di¬ 
rectly with its controlling and protective devices. (2) The metering- 
or load-panel, with which the voltmeter, ammeter, and wattmeter 
connect. (3) The feeder-panel, with which the outgoing feeders, 
with their controlling-switches, connect, and which might be called 
the distributing-panel. (4) The testing-panel, to which the ground- 
detectors, lightning-arresters, etc., may be connected. 



Dl. VOLTMETER 



WATTMETER 


LOAD PANEL 




Fig. 25.—Elements of a switchboard. 


The ammeter or ampere-meter is an instrument through which the 
entire current of the circuit to which it is connected passes. By in¬ 
dicating the amperes it practically records the number of lamps in 
service, unless motors are also feeding from the line. This instrument 
is always placed in series in the line, not in multiple; if placed other¬ 
wise it would be destroyed or greatly disabled. The voltmeter is 
always placed in multiple with the circuit (Fig. 26) whose pressure 
it indicates. The reason for the difference in connections of the am- 



















THE SWITCHBOARD 


445 

meter and voltmeter is found in the great difference in the resistance 
they represent. 

The ammeter has the least possible resistance; the voltmeter, on 
the contrary, the highest possible resistance. The ammeter would 
cause a short circuit to the line if placed across its terminals; the 
voltmeter, if placed in series, would completely block the passage of 
the current. 

The wattmeter indicates the product of the two elements of power 
noted by the ammeter and voltmeter (watts = amperes X volts), and 




Fig. 26.—Connections of a voltmeter and ammeter. 

thus gives a record of the output of power during an hour’s, day’s, 
week’s, or month’s operation. It is an excellent record of the output 
in power obtained for a given period from a given tonnage of coal. 

The circuit-breaker and fuses are of the same class, though of 
different construction and operation. They both serve to open the 
circuit (Fig. 27) when an overflow of current occurs. The fuse melts 
or volatilizes, and thus destroys the continuity of the circuit it con¬ 
nected. The circuit-breaker, through the medium ol a controlling 
electromagnet, opens a switch when an overflow occurs. 

Both devices are, in this sense, comparable to the safety-valve 
of a boiler; this applies particularly in the case of the circuit-breaker, 
whose operation is electromechanical. As is self-evident, the fuse 
must be replaced, whenever it blows, with a new and equivalent 
piece of fusible metal. The circuit-breaker is simply ieset bv means 





















446 


THE SWITCHBOARD 


of a catch which engages with the armature of the controlling electro¬ 
magnet. When that armature moves against the tension or pressure 


MMN LINE OPENED 



Fig. 27.—A single pole circuit-breaker with action of magnet and spring shown. 

of a set-spring—which is impossible unless the current rises above 
a certain optional value—the catch is released, and the carbon-armored 
jaws of its switch fly open, breaking the circuit it thus protects. 

THE LIGHTNING-ARRESTER 

This device is simply an air-gap interposed between the line and 
the earth (Fig. 28) through the medium of two pieces of metal slightly 
separated from each other. The idea involved is that static dis- 



A DOUBLE POLE NONARCING 
ARRESTER 

Fig. 28.—Two types of arresters in use. 






































































THE SWITCHBOARD 


447 


charges will jump the air-gap to the earth instead of continuing 
along the conductors. The highly oscillatory nature of the discharge 
leads to this conclusion, tor the reason that a rapidly moving quantity 
of electricity finds a greater difficulty in permeating a conductor the 
more rapidly it oscillates. 

At a very high rate of oscillation—that of a lightning-discharge 
in fact—the conductor becomes less conductive than the air. The 
gap in the arrester thus permits the charge to choose and pass into 
the earth. A wire leading up from an earth-connection to a piece 
of metal 1 —the said piece of metal being opposite and near to another 
connected to a line wire—represents an arrester in its simplest form. 
Variations of this idea predominate in practice as indicated by many 
manufactured types. 

A GROUND-DETECTOR 

As its name implies, this is a device by means of which a ground 
between the mains, feeders, or branches and the earth is indicated. 
It is of sufficiently simple construction to warrant no other explanation 



Fig. 29.—Ground-detector. 


than that it consists of two lamps in series (Fig. 29) across a 110-volt 
line. The junction between the lamps is grounded or earthed. When 
a lamp on one side glows brighter than that on the other, it means a 
ground on the side of the dim lamp. It is a simple and effective 
















THE SWITCHBOARD 


448 

method of determining the condition of the circuit before the power is 
turned on. 

The existence of a ground, when discovered through the use of 
this device, calls for immediate investigation and a systematic search. 
In order to facilitate the test, the feeder-switches should be all opened 
and the dynamo-mains tested first. If this test does not result in 
discovering the ground, each feeder-circuit should be thrown in, one 
after the other, until the lamps again show the discrepancy in illu¬ 
mination noted at the beginning. 

The last switch to be closed to effect this result is the one govern¬ 
ing the circuit or circuits in which the ground exists. The investi¬ 
gation is then made with respect to the heavier and then with the 
subsidiary branches of this particular feeder-circuit, until the fixture, 
chandelier, motor, or other source of trouble -is discovered and the 
fault remedied. A daily test to protect the system is necessary be¬ 
cause a ground on both legs, if heavy enough, would constitute a short 
circuit. 


STORAGE-B A TTERIES 

The storage-cell is employed for a distinct purpose in central- 
station, power-house, and private-plant work. Its application is best 
found in central-station and power-house service as a means of averag¬ 
ing up the day- and night-load. If there is a very heavy call made 
for current—a demand beyond the load-limit of the generators—the 
storage-battery serves the useful purpose of adding such of its quota 
as is necessary to meet the demand. 

If the demand is frequent but spasmodic there is no substitute 
for it in an electrical or an economic sense. In other respects the 
storage-battery, merely as a convenient electrochemical device for 
transforming electrical energy into chemical energy, is an interesting 
and commercially useful invention. Its characteristics may be readily 
comprehended in the following terms: 

TYPES OF STORAGE-BATTERIES 

There are two types of storage-cell, the Plante and the Faure. 
The Plante consists of lead plates that have undergone the process 
(Fig. 30) called “forming,” whereby the lead-surface for a considerable 


THE SWITCHBOARD 


449 


depth has been converted into an oxide of lead. The positive 
plates—that is to say, the plates always connected with the positive 
pole of the dynamo—turn into a spongy reddish or chocolate-colored 
mass. The negative plates, always connected to the negative pole of 
the charging current, turn gray or slaty in color, due to the develop¬ 
ment of dioxide of lead. 

The peroxide of lead or positive plates and the dioxide of lead 
or negative plates are thus the recipients of the electricity sent in, 
storing it up to a certain point, as the popular expression goes, 
called “the capacity of the plates” or “cell.” The solution used is 
that of a 20-per-cent, sulphuric-acid mixture, or four-fifths water and 



electricity entering and 

PRODUCING AN ELECTRO-CHEMICAI 
CHANGE 


ELECTRICITY LIGHTING 
A LAMP DUE TO THE 
ELECTRO-CHEMICAL CHANGE 


Fig. 30.—Conversion of lead into active material, and then the production 

of electricity. 


one-fifth acid. The acid employed for this purpose is comparatively 
pure; otherwise distressing and injurious local troubles will develop. 
The Faure cell differs from the Plante in the respect that the oxide is 
not formed by a slow electrical process of charging and discharging 
during a period of many weeks, as was the old and original process, 
but by mechanically applying the two oxides in the form of a paste. 
The pasted grid of lead or some lead alloy came into extensive use 
(Fig. 31), and its interstices were filled with a paste of lead oxide and 
glycerine. The positive grid originally received a red-lead paste, 
which, through a comparatively brief forming process, was ieadil\ 
converted into peroxide of lead. The negative plate received a paste 

































450 


THE SWITCHBOARD 


of litharge, a lower oxide of lead, a comparatively brief forming process 
converting this as well into a dioxide of lead. 

The idea in connection with both plates was to get a spongy mass, 
in close adherence to the grid supporting it, during the process of 





T 


□ □ □ □□ 
TDCmiDD 
□ □ □ □ □ 
□ □nan 


oooo 
oooo 
oooo 
oooo 
p ooo 


HOLE for paste plugs of finely divideo lead 


Fig. 31.—Appearance of grid to which paste or a process is applied to 

rapidly form it for service. 


manufacture. The capacity of the plates individually and collectively 
was thus raised to a certain practical working maximum by which 
they were rated when sold. This rating is in ampere-hours, a term 
meaning the number of amperes normal discharge for a certain num¬ 
ber of hours. For instance, 100 ampere-hours would mean about 10 
amperes discharge for 10 hours; a 250-ampere-hour capacity would 
mean about 25 or 30 amperes respectively for 10 or 8 hours. The 
lower the rate of discharge comparatively, the longer the number of 
hours of service, a sudden heavy call for current beyond the normal 
rate being likely to cause serious damage to the plates. 

The pasted plate and the pure-lead plate are used in conjunction 
in the following manner: the positive plate is made in the majority 
of cases of finely divided lead, upon which the electrical action is very 
rapid. This plate is used in connection with a pasted negative plate. 
The positive wears out the more quickly, and is therefore replaced 
the oftener. It must therefore be made as strong as possible be¬ 
cause of the peculiar deterioration to which it is subject. The nega¬ 
tive plate may outwear the positive two to one or even three to 
one in some instances. 














THE SWITCHBOARD 


451 


DIFFICULTIES WITH PLATES 

The difficulties with storage-battery plates are at least twofold: 

First, they are apt to sulphate if left too long in the solution without 

• • 

being well charged. Second, they are likely to bend or buckle under 
the influence of a very heavy discharge. The sulphating means a hard, 
flaky, white coating of sulphate of lead (Fig. 32), which is removed 
only with great difficulty by scraping or by heavy charging and dis¬ 
charging. The acid in this case simply attacks the lead-surface 
when the plates are well discharged, and starts a distinct chemical 
action. The moral of this is never to permit a storage-battery to fall 
very low without recharging. 

The battery is generally over 2 volts when normal, and when well 
emptied of its energy about 1.9 volts or a little lower. This, however, 
is the limit of discharge 
per cell for ordinary 
forms of service. The 
buckling or bending is 
caused by the sudden 
strain on the plates by 
an inordinate discharge. 

The rate of discharge 
which is considered safe 
is given with each type 
of cell by the manufac¬ 
turer, and, if possible, 
should not be exceeded. 

The buckling that is so 
apt to occur in the plates has the effect of loosening the plugs of 
active material, which may drop between the plates and cause an in¬ 
ternal short circuit. It may also make the plates touch at various 
points unless adequately remedied. The means employed to remedy 
this difficulty is simply that of making plates sufficiently rigid to with¬ 
stand the strain without injury. In other words, the plates of modern 
batteries are made thick enough to remain unaffected throughout 
their period of usefulness. 




LEAD OF WHITISH COLOR 

Fig. 32.—Patches of sulphate on surface, and 
bending of plate. 














452 


THE SWITCHBOARD 


EFFICIENCY OF STORAGE-CELLS 

A comparative test of the efficiency of storage-cells is made by 
simply sending into each a given amount of power and taking it out 
again up to a certain point. The voltage of the cells will give a fair 
idea of the relative value of each cell under the circumstances. But 
this is not conclusive, as it is necessary to take into consideration 
the weight of each cell and its period of usefulness in making a fair 
estimate of its respective qualities. 

Cells are made for portable and for stationary use; the weight 
question is an important one in the first case, though unimportant in 
the second. Portable cells always deteriorate much quicker than 
those occupying a fixed position. Each square foot of active plate- 
surface will give certain maximum and minimum capacities in ampere- 
hours. Each set of plates will last a certain period of time under the 
influence of a certain course of treatment. The commercial problem 
is that of increasing their period of usefulness; the scientific problem 
is that of increasing their capacity for a given size and weight and of 
eliminating characteristic defects. 


THE BATTERY-ROOM 

A battery-room is best designed with reference to ventilation, 
drainage, heating, water-supply, aisle-space, floor-construction, and 
absence, as far as possible, of metal-work. The charging of a storage- 
battery means the development of acid-spray, whose effects are highly 
deteriorative. Not only must the room be constructed so as to 
be protected from this evil, but it must be ventilated effectively. 
Openings near the ceiling at one end, and near the floor at the other 
end, are the best means of securing a clean atmosphere. The sloping 
of the floor must be sufficient to thoroughly drain it when wetted 
through overflow, accumulations, or during the process cf flushing it 
out. 

Too much cold is effective in reducing the capacity of the cells; for 
this reason the battery-room must be kept at a moderate temperature 
during the winter season. Inspection is necessary at all times, and 
in order to accomplish this readily the cells must be arranged so as to 


THE SWITCHBOARD 


453 


be easily accessible. Refilling with water or solution must not be a 
difficult task in a battery-room. Having the cells low enough down, 
with an aisle on each side, is a good plan if space permits. 

The use of asphaltum paint is a good protection against acid-spray 
wherever it may deposit; and the floor of the room should be made 
of vitrified brick laid on concrete and filled in with pitch. To have 
water conveniently at hand is imperative in a battery-room, though 
the use of distilled water is far more preferable. If floor-space is 
limited the cells must be arranged in tiers, each of which must afford 
enough overspace to readily handle, inspect, and, if necessary, remove 
defective cells or plates. 


CHAPTER XXVII 


LIGHTING AND LAMPS 
ELECTRIC LAMPS 

The sources of electric illumination have developed sufficiently 
to represent a distinct department in themselves, and are of equal im¬ 
portance to the system or systems of electric lighting in vogue, with 
their characteristic accessories. Electric lamps are sufficiently varied 
in principle and construction to represent a classification of the 
greatest interest, and they may be divided into the following types: 

1. Incandescent lamps that employ a vacuum to protect the in¬ 
candescent mass in use from the action of the air. 

2. Incandescent lamps that do not employ a vacuum, but use an 
incandescent mass which is inherently inoxidizable. 

3. Arc-lamps which employ two carbons that burn in the air 
and that consume in about eight or ten hours. 

4. Arc-lamps which employ two carbons that burn in the air, the 
carbons having a metal core, which develops a comparatively long arc 
of unusual light-giving power. 

5. Arc-lamps which employ two carbons that burn in a closed 
globe, through which they last 100 or more hours. 

6. Incandescent-vapor lamps that use an incandescent mercury 
vapor to produce illumination. 

7. Ineandescent-tube lighting that is effected in long tubes devoid 
of air, but filled with a highly illuminative gas when affected by a cur¬ 
rent of the proper pressure and character. 

The incandescent lamp with a carbon filament and the closed globe 

or enclosed arc-lamp are the two most prominent types of lamps 

(Fig. 33) in use to-day. The arc-lamp which burns with exposed 

carbons has been modified by the introduction of a metal core and a 

specially impregnated carbon, and thereby given a new lease of life. 

It bears the general title of the flaming arc for reasons that will be 

obvious when it' is realized that metallic vapor is effective in this 
454 


LIGHTING AND LAMPS 


455 



Fig. 33.—Types of electric-light sources in present use. 


respect to a marked degree, by enabling an ordinary arc to be elon¬ 
gated sufficiently to give light not only from the carbon terminals, 
but from the arc itself. 


THE INCANDESCENT LAMP 

The carbon filament of an incandescent lamp is obtained by 
carbonizing a fine string of cellulose, enclosing it in a glass globe from 
which the air has been removed, providing it with platinum leading- 
in-wires, so that both the metal and the glass will expand and contract 
together and thus preserve the vacuum, and attaching it to a suitable 
base for commercial purposes. A lamp of this character is generally 
used on a 115-volt circuit, and takes a current of from .4 to .5 of an 
ampere. The value of the lamp commercially is naturally based upon 
three considerations: (1) The cost in barrel lots; (2) the life in hours 
of normal candle-power, and (3) the amount of candle-power per unit 
of power; as, for instance, the number of watts per candle or per lamp 
of 16 candle-power. 






































456 


LIGHTING AND LAMPS 


LIGHT 16 C.P. NEW 
FIRST 100 HOURS 


LIGHT 12 C. P 
AFTER 400 HOURS 


LIGHT 10 C.P 
AFTER e00 HOURS 





Fig. 34.—Relative light of old and new lamps. 


The cost, durability, and efficiency have been the governing influ¬ 
ences in developing incandescent-lamp manufacture to its present 
point of perfection. In the central station or private-plant the effi¬ 
ciency and durability of lamps are points of vital importance. The 
question in this case is fundamentally that of the cost of the candle- 
power hours. Incandescent lamps vary in this respect, one producing 
more candle-power hours at a given power or watt-consumption than 
another. The lamp lasts from 500 to 600 hours under ordinary con¬ 
ditions, the unit of power adopted being that of 16 .candle-power. 

This light, however, 
varies in efficiency as 
the life of the lamp 
increases. It grows 
less illuminative with 
a given amount of 
power, and therefore 
becomes less efficient. 
In fact, the net con¬ 
clusion inevitably 

reached is that old lamps are very wasteful (Fig. 34), as may be readily 
shown as regards the light they give and the watts they consume. For 
instance, a new 16 candle-power lamp will use .4 of an ampere and 
115 volts, or .4x115 = 46.0 watts. At the end of 600 hours it will 
require 55 or 60 watts to give the same light. 

The fact that the old lamps do not break is a temptation to use 
them; but the difference between 60 and 46 watts is 14, or nearly 
33J per cent, more power. If the pressure is not raised the old lamps 
will give no more than 10 or 12 candle-power, thus causing a waste 
either way of practically 33J per cent, of the fuel. Old lamps or 
inefficient lamps are simply coal-wasters, which cost more in fuel than 
it would cost to buy new lamps. 

As the primary purpose of a plant is to supply a certain amount of 
light, it seems self-evident that the keeping of it up to a normal 
value is a responsibility that cannot be carried out without adequate 
means. For this reason the efficient lamp is a saving, because it 
means not only less coal, but less wear and tear of machinery, less rate 
of depreciation, in fact, in providing satisfactory lighting. With re¬ 
spect to the arc-lamp, 10 amperes and 115 volts in incandescents 



















LIGHTING AND LAMPS 


457 


will light about 20 or 25 lamps of 16 candle-power, or produce about 
300 or 400 candle-power. An arc-lamp of the enclosed type, taking 
the same watts, will produce from 1,200 to 2,400 candle-power, the 
ratio of light produced being as 4 or 6 is to 1 in favor of the arc 
as far as efficiency is concerned. 


THE NERNST LAMP 

This lamp, in which a piece of rare oxide burns in the open air, 
is more efficient than the incandescent lamp so called, because the 
temperature of the incandescent mass is raised so much higher. In 
other words, the whole question of efficiency in incandescent lamps 
hinges upon that of temperature. If a carbon filament could stand 
the temperature at which the rare oxide burns (Fig. 35), the efficiency 
would double. Instead of taking from 3 to 4 watts per candle-power, 
it would take from 1.5 to 2 watts. But carbon will not stand this 
heat under ordinary circumstances for any length of time. 


GLOWER 


TEMPERATURE 
IS HIGHER THAN 
CARBON FILAMENT 


1 .5 WATTS PER C. P. 


FILAMENT 



ABOUT 3 WATTS PER C.P. NEW 


Fig. 35.—Power consumed for light at higher temperatures. 


The lamp mentioned above, however, using the rare oxide in air, 
requires that this oxide be primarily heated befoie sufficient cui rent 
will pass to heat it individually. An automatic heatei is theiefoie 
used for this purpose. The filaments of these lamps are technically 
called “glowers,” of which one, two, or more may be used in a giwn 
case. The light is produced at the rate of about 1.5 watts per candle- 
power, or at twice the average efficiency of new incandescent lamps. 



























458 


LIGHTING AND LAMPS 


THE OPEN ARC 

By the term “open arc” is meant the type of lamp in which the 
carbons burn in the open air. In this type the carbon tips and the arc 
combine to produce light. The tips are in some instances the most 
effective, particularly in the enclosed type. The arc gives an average 
rated spherical candle-power of about 2,000 with a current of 10 
or 12 amperes and about 50 volts. This means two lamps in series on 
a 115-volt circuit. For high-tension lighting the lamps are arranged 
in series, 2,000 volts being sufficient to light forty lamps in series. 
The difficulty and expense are found in the removal of the carbons, 
their cost, and the general attention required. 

THE FLAMING-ARC LAMP 

The accentuation of the light and length of the arc itself, as pre¬ 
viously stated, is a source of light which, bearing the descriptive name 
of the “flaming arc,” has proved exceedingly efficient as an outdoor 


METAL CORED 
CARBON 



CARBON ENDS AND ARC MAINLY FROM THE ARC 

Fig. 36.—Principle of the ordinary and the flaming arc lamp. 

illuminant. The production of gases limits its use for indoor illumina¬ 
tion, except in such cases where the ventilation is excellent, thereby 
rendering the gases undetectable. The lamps burn two in series, on a 























LIGHTING AND LAMPS 


459 


115-volt circuit, the carbon tips (Fig. 36) as well as the flame of the 
arc, with its metallic constituents, developing an enormous illumination 
—at least three or four times greater than that of the ordinary arc as 
far as effective light is concerned. 

The carbons are replaced about every day, and the lamp inspected 
and readjusted no oftener than the ordinary open-arc lamp. A resis¬ 
tance in series is employed, placed in the upper part of the lamp, to 
limit the current when supplied with a higher voltage than necessary. 
The carbons in this particular type are held at an angle with the 
vertical plane, thus equably reflecting the light from the flaming arc 
as well as permitting it to be well distributed spherically. By means 
of the carbons the light developed is of a golden or a reddish tinge. 
The candle-power is about 4,000 per lamp or over, and is remarkably 
effective on account of its peculiar quality due to the salts used to 
impregnate the carbons. 


THE ENCLOSED ARC 


This is an open arc with the carbon-ends adjusted to a globe 
supplied with an outlet-valve. The oxygen is quickly burnt up, 
and the burnt air (Fig. 37) in conse¬ 
quence has little or no effect upon the 
carbons, which thus last 100 or 150 
hours instead of 10 or 15. 

A saving in carbon and care is thus 
in evidence, which is counter-balanced, 
however, by the deposits on the globe 
and the cutting down of the light. 

These lamps take about 100 volts, in¬ 
stead of 50, on account of the length of 
the arc, and are therefore heavy users of 
current and pressure on 115-volt cir¬ 
cuits. The economic question is that of 
evaluating the cost of carbons and labor 
against the cost of extra power. Into 
this estimate the consideration of safety 
must enter on account of the closed 
character of the lamp and the resultant 
candle-power. 



Fig. 37.—The carbons burn with 
flat ends. 














460 


LIGHTING AND LAMPS 


MERCURY-VAPO II L A M P 

Iii this lamp a tube with electrodes forms an arc of mercury, in 
which band of dazzling light, however, all red rays are missing. This 
defect exhibits itself in the development of ghastly flesh-effects, green 
and blue (Fig. 38) causing a livid appearance of the lips, face, and 
hands. For this reason this lamp cannot be used for domestic or 
ornamental lighting, but is serviceable for docks, factories, ware- 



Fig. 38.—Experiment with red glass—which can only transmit red rays—to prove 

the absence of red light. 

houses, etc. The tube is automatically tilted to start the arc by per¬ 
mitting a thin stream of mercury to volatilize between the electrodes. 
The efficiency of this lamp is high enough to establish its commercial 
value on a permanent basis. 

VACUUM-TUBE LIGHTING 

The use of a 150-foot tube, through which an alternating current 
passes, is a development of Geissler’s early experiments on a commer¬ 
cial scale. The so-called vacuum, in conjunction with certain gases, 
is a source of illumination which has found a place in daily practice. 
The absence of wires in all but one spot where the tube enters and leaves 









































































































LIGHTING AND LAMPS 


461 


after making its circuit of the room, is an interesting feature. The ' 
length of tube is suspended (Fig. 39) by brass clasps, and the light is 
estimated from the candle-power per inch. 



Fig. 39.—Vacuum tube lighting in daily practice. 


The power used is alternating, and is transformed into a current 
with a particular form of wave. The action of this upon the gas in the 
tube causes a uniform glow of the pleasantest character. No brilliant 
centre of light appears, but a type of diffused radiance that is highly 
suitable to indoor illumination. The efficiency of this system is 
claimed to be greater than that of the incandescent lamp. 

ELECTRIC-LIGHT EQUIPMENTS 

There are many methods in use of obtaining systematic rotation 
in a mechanical sense; and it is quite evident that rotation of this 
character is suited in every respect to electric lighting through the 
medium of the dynamo. The well-known devices producing this type 
of power are steam-engines or turbines, gas- or oil-engines, and water¬ 
wheels. Each deserves separate consideration in a treatment, how¬ 
ever brief, of this subject. 

STEAM ELECTRIC PLANTS 

The consumption of steam in reciprocating engines or turbines 
obtained from boilers represents in total the elements of a steam- 
plant. The boiler and its accessories, the engine or turbine, and 






















462 


LIGHTING AND LAMPS 


the generators and switchboard, with its light- or power-circuits, 
comprise the modern equipment whose size and character of service 
give it the name of private plant, central station, or power-house. 
The fact that the electricity is consumed privately, does not necessarily 
limit the size of the plant. A private plant may be far greater than a 
central station, yet differ from it in purpose and hours of service. A 
central station is a public dispenser of light and power, operating under 
a municipal franchise. A power-house, in contradistinction, is a street- 
railway equipment, sending out power primarily for the cars along the 
route, yet incidentally supplying electricity for light and power. 

These three great equipments are thus defined as the private plant, 
however large, having no franchise; the central station, generating 
electricity for light and power purposes; and the power-house or street- 
railway plant, whose franchise is directly intended to have it serve 
street-railway interests. The general efficiency of these equipments is 
dependent upon the character of the boilers, engines or turbines, and 
generators in operation. The weight of coal consumed per horse- 



MECHANICAL POWER ELECTRIC POWER LIGHT OBTAINED BY 
OBTAINED OBTAINED INCANDESCENT LAMPS 


Fig. 40.—Relative light effect obtained from a given amount of coal by electric 

lighting by incandescent lamps. 


power or kilowatt hour and the cost of handling that power until it 
is paid for by the consumer constitute the economic problem presented 
to the manager of large or small equipments of the central-station 
class. 

The range of efficiency for the steam, generating, and transmitting 
and distributing sections are all well known, as likewise that for the 
various types of lamps. These facts may be arranged (Fig. 40) in a 
convenient form for reference. 

1. The steam section has an efficiency of from 14 to 16 per cent, 
from the coal to the mechanical energy delivered. 





LIGHTING AND LAMPS 


463 


2. The generating section has an efficiency of from 90 to 95 per 
cent, from the engine or turbine to the switchboard. 

3. The transmitting and distributing section has an efficiency of 
from 90 to 95 per cent, from the switchboard to the consumers’ lights. 

4. The illuminating section, or lamps, have an efficiency of from 
3 to 10 per cent, from the circuit terminals to the candle-power pro¬ 
duced. The rating would be about 3 per cent, for incandescents, 
6 per cent, for Nernst and mercury vapor, and about 10 per cent, 
for arc-lamps in general. 

It seems a very difficult matter at present to generate light-waves 
without first developing heat-waves, as, for instance, in all the illu- 
minants known, with the possible exception of the vacuum-tube. 
The making of light is therefore restricted by the limit of present 
scientific knowledge. The only gain, outside of the element of depre¬ 
ciation—which is reducible only by strengthening or by reducing the 
number of deteriorating parts in a plant—is by cheapening the original 
power-supply. This is a condition implied by the fixity of the general 
efficiencies in all but the starting-point. Here the water-power 
proposition becomes of interest, as well as that concerning the develop¬ 
ment of power from explosive engines. 


WATER-POWER PLANTS 

A stream of quickly flowing or falling water, developing enough 
energy to move a water-wheel or turbine all the year round, is an 
interesting possibility if it is near a city or town. If many miles away 
from a large community, its usefulness will be governed by its power. 
It pays to transmit enough power thus obtained, if the supply is com¬ 
paratively regular. Otherwise its value is limited, as when the supply 
varies greatly from summer to winter or ceases altogether temporarily. 

A variable source of power may mean an auxiliary steam-plant, 
making the economic issue doubtful in the extreme. Power thus 
obtained, however, is cheap if regular, and simplifies the electric-light- 
and-power proposition, provided the distance of transmission is not so 
great that the investment for poles, insulators, and conductors repre¬ 
sents an unreasonable figure. 

A turbine or water-wheel varies in efficiency from 70 to 85 per cent. 
The delivery of that power at a distance costs, roughly, in proportion 


464 


LIGHTING AND LAMPS 


to the distance. This is a problem best solved by reference to exist- 
ing data concerning similar power-transmission plants. Hydro-electric 
plants, as they are called, really consist of only the water-wheel, the 
generator, the switchboard, and the outside circuits. Cheap power 
is the natural consequence of an equipment of this character if intel¬ 
ligently constructed and handled. 


GAS-ENGINE ELECTRIC PLANTS 

Instead of burning coal the process of distilling it for its explosive 
gases, and using them as a source of power, is becoming prevalent. 
Small gas-making plants of this character are called “gas-producer 
plants.” The government tests show an immense increase in fuel- 
efficiency in distilling coal and instead of burning the coal under a boiler, 
exploding the gas to gain power in a gas-engine. The use of so-called 
illuminating-gas in a gas-engine, and the application of the resulting 
power to the production of electricity, is becoming more emphasized in 
central-station practice than ever before. Private plants thus equipped 
are numerous on account of the elimination of the boiler and its acces¬ 
sories and the consequent simplification resulting. If, instead of the 
boiler, a gas-producer plant is installed wherein the power-supply is to 
be great enough, the expense for gas is so reduced that a kilowatt hour 
costs less than one-half of its production in a steam-plant of equal 
size. 

The depreciation of gas-engines and their accessories is therefore 
balanced up against steam-engines and their accessories in forming 
a correct estimate of the cost of operation. The capacity, horse-power, 
speed, and weight of a line of gas-engine plants for small installations 
are given in the following table, with the form of the manufacturers’ 
guarantee: 


Kilo¬ 

watts. 

Horse¬ 

power. 

Speed. 

Type. 

Weight 
of engine. 

Floor- 

space, 

inches. 

Weight of 
direct- 
connecting 
unit. 

Floor- 

space, 

inches. 

No. lights, 
16 candle- 
power. 

2* 

6 

400 

Vertical. 

2,050 

36 X 39 

2,850 

36X64 

50 

7 

12 

360 

2 cylinder. 

3,200 

38 X 42 

5,700 

38X96 

120 

10 

18 

350 

2 cylinder. 

4,400 

40 X 44 

7,200 

40 X 102 

180 

20 

30 

300 

2 cylinder. 

8,200 

53 X 57 

13,500 

53 X 122 

360 
























LIGHTING AND LAMPS 


465 


Manufacturers’ Guarantee. 


We install these plants with the guarantee that there will be no 
noise from the exhaust. We guarantee every machine against 
breakage or undue wear for one year. 


To recapitulate, with reference to the foregoing facts the present 
practice shows the limit of power- and light-efficiency, and indicates, as 
a means of improving the net efficiency, the necessity for either cheap¬ 
ening the power or changing the lighting system in vogue, not super¬ 
ficially, but fundamentally. Cheapening the power is an obvious 
way, relatively, but this is not true of the light. It must be under¬ 
stood that because of the comparatively low efficiency of the light, 
even of the flaming arc, it becomes imperative to make power cheaper 
to cheapen electric lighting. 

The intermediate machinery between the heat or gas-explosion 
and the light will probably remain unchanged for some time. Progress 
therefore will be best evidenced scientifically, and subsequently com¬ 
mercially, by the development of a plan or system by means of which 
the long heat-waves are cut entirely out, and the short light-waves 
are produced with greater directness. This would mean cold instead 
of hot light at the source, and an immense saving in energy now 
uselessly and widely dissipated. 

QUESTIONS AND ANSWERS ON CHAPTER XXI \ 

Question.—How may the operation of the dynamo be best de¬ 
scribed ? 

Answer.—As the movement of conductors through lines of foice, 
or the movement of lines of force through conductors. 

Question— How do the electromotive forces of a motor and dynamo 
serve different purposes? 

Answer.—The electromotive force generated in the armature of a 
motor is opposite to the electromotive force sending the current in, 
and acts as a regulator. The electromotive force of a dynamo is 
used to send the current through the circuits and their resistances. 

Question.—What is produced in conductors cutting lines of force, 
or in lines of force cutting conductors ? 

Answer.—Electromotive force is produced within the conductois. 



466 QUESTIONS AND ANSWERS 

Question.—How does the alternator and the direct-current gen¬ 
erator differ? 

Answer.—The direct-current generator uses a commutator in order 
to send out a current flowing always in the same direction. The 
alternating-current generator uses collector-rings, which permit all 
the alternations generated within the armature to occur outside in 
connected circuits. 

Question.—What is the formula for calculating electromotive force? 

Answer.—The volts generated equal lines of force X revolutions 
of the armature per second X the armature-conductors -f- 100,000,000. 

Question.—What reverses the direction of a current in a conductor? 

Answer.—The fact that it is being moved past a north pole or a 
south pole. The electromotive force tends to send a current in one 
direction when the conductors pass a north pole, and in the reverse 
direction when they pass a south pole. 

Question.—What is the action of the commutator and brushes? 

Answer.—To permit all positive impulses to flow into one brush 
or set of brushes, and all negative impulses to flow into the other 
brush or other set of brushes. 

Question.—Where do the positive and negative impulses of current 
come from? 

Answer.—From conductors which pass the north and south poles 
respectively in a two-pole or multipolar field, and with which commu¬ 
tator bars are connected; these bars transmit the positive and nega¬ 
tive currents to the brushes. 

Question.—What kind of current is naturally generated in a two- 
pole or multipolar direct-current generator? 

Answer.—A series of reversing electromotive forces, or what is 
called an alternating current, which is rectified or commutated. 

Question.—How are dynamos classified with respect to the char¬ 
acter of their currents? 

Answer.—As alternating- and direct-current generators. The 
direct-current machines are further classified as series-, shunt-, and 
compound-wound generators. 

Question.—Of what use is the transformer? 

Answer.—To raise or lower the voltage; the volts are raised or 
stepped up for transmission, and lowered or stepped down when the 
current is to be distributed. 


QUESTIONS AND ANSWERS 


467 

Question. How is the field regulated, and what is the effect 
of this regulation on the voltage? 

Answer. The field is regulated by means of a resistance in series. 
When this resistance is increased or decreased the current in the 
fields decreases or increases. A more powerful field means more lines 
of force and more volts, and a weaker field means less lines of force 
and less volts. 

Question.—Upon what principle does the series-wound dynamo 
regulate to preserve a constant current and a varying potential? 

Answer.—Upon the principle that some armature-conductors pro¬ 
duce more volts than others when in certain positions in the field. In 
consequence the brushes may be made to touch either where the pres¬ 
sure is high or low by an automatically controlling electromagnet 
in series with the line. 

Question.—How is a shunt dynamo regulated for a constant 
potential and a varying current? 

Answer.—By controlling the current entering the fields the shunt 
dynamo is made stronger or weaker, thus enabling the armature to 
produce a higher or a lower voltage to compensate for the armature- 
reaction in the form of drop and a reactive field. 

Question.—How is regulation accomplished in a compound-wound 
dynamo to preserve a constant potential with a varying current? 

Answer.—By means of an adjunct coil in series with the main line, 
the increasing current of the armature enables the dynamo to produce 
more magnetism. This magnetism is so regulated that its increase 
approximately counterbalances the loss in magnetism sustained by 
the reactive effect of the armature. It also supplies enough extra 
lines of force to enable the armature to generate as many more volts 
as are needed to make up for the drop within its conductors. 


QUESTIONS AND ANSWERS ON CHAPTER XXV 

Question.—What two cases are presented with respect to grounds? 
Answer.—A ground in one or more coils. 

Question—What is the effect of a heavy ground? 

Answer.—Heat in the coil or coils thus affected. 

Question.—How is a short circuit explained? 

Answer.—As a case in which the current enters a path of lower 
resistance. 


468 


QUESTIONS AND ANSWERS 


Question.—What is done to dispel moisture? 

Answer.—The coil, if possible, is carefully baked. 

Question.—Name some of the causes of sparking. 

Answer.—Among the principal causes of sparking may be men¬ 
tioned: too great a load, a wrong position of the brushes, loose 
brushes or projecting mica, a general design that is poor (such as a 
badly proportioned air-gap), etc. 

Question.—When should a hard or a soft brush be employed? 

Answer.—When the commutator is hard-drawn copper the carbon¬ 
brush should be used. When the commutator is of softer metal a 
brush must be used that will not grind the commutator into metallic 
powder. 

Question.—When is sparking ineradicable? 

Answer.—When the design is bad, by which is meant that the 
relationship between the thickness of the air-gap, the arc of the pole- 
piece, and the load the armature bears, is not correct. 

Question.—At what instant does sparking generally occur? 

Answer.—When the conductor enters the lines of force of a new 
pole after leaving one of opposite polarity. 

Question.—What is the purpose of the pole-piece fringe? 

Answer.—To permit a sparkless reversal of the current. 

Question.—If the dynamo will not generate, what are the causes 
which may be regarded as effective? 

Answer.—There may be no residual field; the magnets may have 
the same polarity; the field-coil may have an open circuit; the arma¬ 
ture-connections may be open or may be short-circuited, etc. 

Question.—What causes black bars in the commutator? 

Answer.—A broken coil in the armature causes black bars between 
the ends of the break. 

Question.—What are the causes of a hot armature? 

Answer.—An overload, short-circuited coils on the armature, 
and very thick conductors. 

Question.—W hat are the types of direct-current motors that are 
in use? 

Answer.—The series, the shunt, and the compound wound. 


469 


QUESTIONS AND ANSWERS 

Question.—What causes heat in the commutator? 

Answer. -Bad contact between the brushes and the commutator, 
a small commutator, too much pressure from the brushes, or a brush 
of too great a resistance. 

Question. What is the effect of increasing or diminishing the 
current? 

Answer. The heat varies as the square of the current in amperes. 
Twice the amperes means four times the heat, three times the amperes 
nine times the heat, etc. 

Question. What general rule may be depended upon with regard 
to heated bodies, whether heated by electricity or by any other means? 

Answer. That the amount of external or radiating surface will 
govern the rise of temperature with any steady supply of heat. 

Question.—In what important respect do steam and electrical 
practice differ? 

Answer.—In steam practice the effort is made to prevent the heat 
from radiating; in electrical practice the radiation of the heat from 
conductors is obligatory. 

Question.—What will happen to a series motor with no load? 

Answer.—It will wreck itself by attaining a destructive speed. 

Question.—How is a shunt-wound motor started up? 

Answer.—Always with the field full on, and a rheostat in series 
with the armature. 

Question.—What is the purpose of a compound winding in a motor? 

Answer.—To either strengthen the field, or weaken it with a heavy 

load. 

Question.—With what effect will a stronger or a weaker field 
operate, and what are their uses? 

Answer.—A stronger field makes a shunt motor run slower, and a 
weaker field faster, with a given load. A compound winding permits 
this through the influence of the series coil, which may be connected 
so as to strengthen or weaken the field. 

Question.—What is the value of the back electromotive force 
of a motor? 

Answer.—It is equal to the difference between the impressed 
electromotive force and the voltage required to send the amperes at 
any particular point of load through the armature. 


470 


QUESTIONS AND ANSWERS 


Question.—What is the difference in a direct-current motor be¬ 
tween doing the greatest possible amount of work and having a high 
efficiency? 

Answer.—When making the motor do its greatest possible work 
it will be overloaded, run slowly, and thus develop power at a very 
low efficiency. 

Question.—What is an indication of an open circuit in the arma¬ 
ture ? 

Answer.—A high speed, a line of sparks or two burnt bars. 

Question.—What is the back electromotive force of a motor? 

Answer.—The electromotive force developed by the armature- 
conductors cutting the lines of force. 

Question.—What is the electrical efficiency of a motor? 

Answer.—The ratio between the back and the impressed electro¬ 
motive force. 

Question.—What is the commercial efficiency of a motor? 

Answer.—The ratio between the mechanical power taken out 
and the electrical power sent in. 

Question.—What are the causes of noise in motors? 

Answer.—The armature-slots and the pole-tips, the brush on 
the commutator not being properly inclined, a rough commutator, 
and lack of lubrication. 


QUESTIONS AND ANSWERS ON CHAPTER XXVI 

Question.—What is meant by the term “switchboard”? 

Answer.—Technically a board on which switches, protective 
apparatus, measuring-instruments, etc., are found, and by means of 
which the entire system is operated. 

Question.—What are the classes of devices found on a switchboard ? 

Answer.—Measuring-instruments, controlling devices, protective 
devices, regulating devices, and testing devices. 

Question.—How are the circuits classified? 

Answer.—As mains, feeders, branches, and sub-branches. 

Question.—What is a centre of distribution? 

Answer—A point on each floor, or group of floors, from which 
control over those particular circuits may be exercised. 


QUESTIONS AND ANSWERS 


471 


Question.—What is meant by the term “panel board”? 

Answer. Small boards set in the wall that are supplied with 
switches and fuses for a given group of circuits. 

Question. What fundamental form of protection must be supplied 
to circuits in all cases? 

« • 

Answer.—Protection against overflows of current in the form of 
fuses or circuit-breakers. 

Question.—What are the natural parts or sections into which a 
switchboard may be subdivided? 

Answer.—Generating, feeding, and metering sections. 

Question.—What do the ammeter and voltmeter indicate? 

Answer.—The ammeter indicates the extent of the load on the 
dynamo. The voltmeter indicates the pressure at which the current 
is supplied. 

Question.—How do these two instruments differ in design? 

Answer.—The ammeter is made of as low a resistance as possible, 
the voltmeter of as high a resistance as possible. 

Question.—How are ammeters and voltmeters connected up in 
circuit? 

Answer.—The ammeter is always placed in series with the load, 
the voltmeter always in multiple. 

Question.—Of what purpose is a wattmeter in a circuit? 

Answer.—It indicates the total of power used in any period of 
time, as given in watts or kilowatt hours. 

Question.—How does the circuit-breaker operate? 

Answer.—It opens the circuit abruptly through the medium of a 
switch and controlling electromagnet, when the current reaches a 
given value to which the magnet is set to operate. 

Question.—What governs the action of a lightning-arrester? 

Answer.—The oscillatory nature of the discharge, through which 
it finds less resistance in an air-gap than a conductor under certain 
conditions. 

Question.—What is a ground-detector? 

Answer.—A device by means of which the contact between a 
leg of the circuit, or both legs, and the earth, directly or indirectly, 
is indicated. 


472 


QUESTIONS AND ANSWERS 

Question—What would be the result of a heavy double ground? 

Answer.—A heavy double ground is the equivalent of a shoi t 
circuit. If not heavy, it constitutes a source of leakage under normal 
conditions. 

Question.—What is the storage-cell used for? 

Answer.—For the purpose of creating a higher average load-line in 
lighting and power service. It also serves to temporarily increase 
the capacity of the plant. 

Question.—What are the two types of storage-cell that are em¬ 
ployed ? 

Answer—The lead plate or Plante and the pasted grid or Faure 
type. 

Question.—With which plates are the positive and with which 
the negative pole of the generator connected? 

Answer.—The positive pole is always connected with the reddish 
plates, and the negative pole with the gray plates. 

Question.—What is the nature of the solution employed? 

Answer.—A 20-per-cent, sulphuric-acid solution. 

Question.—What is the meaning of capacity in a storage-battery? 

Answer.—The capacity as measured in ampere-hours, or the num¬ 
ber of amperes of current for a certain number of hours. 

Question.—Which is better, a low or a high rate of discharge from 
a storage-battery? 

Answer.—A low rate is better than a high, as the durability of a 
stationary plant is thus increased. 

Question.—What are the main difficulties with storage-cells? 

Answer.—Weight (if used for locomotion), sulphating, and buck- 
ling. 

Question.—What is the cause of sulphating and of buckling? 

Answer.—Sulphating is due to the discharged plates being left in 
the acid solution too long uncharged. Buckling is due to the warping 
or twisting of the plates if too thin or if the discharge is too heavy. 

Question.—What is the efficiency of a storage-cell? 

Answer.—The percentage obtained by dividing the watts taken 
out by the watts sent in. 


QUESTIONS AND ANSWERS 


473 


Question. Which would govern the choice of a certain type 
of cell, high efficiency and weakness or lower efficiency and greater 
durability? 

Answer. The durability of the cell means a greater advantage 
than its higher efficiency without it. 

Question.—What governs the design of a battery-room? 

Answer.—Ventilation, drainage, heating, water-supply, aisle- 
space, floor-construction, and no metal-work. 

Question.—How does cold affect the cell-capacity? 

Answer.—It lowers its capacity, and for that reason the battery- 
room must be kept reasonably warm. 

Question.—What paint is durable in a battery-room? 

Answer.—Asphaltum paint, or a paint not affected by acid or the 
fumes of charging. • 

Question.—How should the cells be arranged? 

Answer.—They are best arranged in tiers one above the other, 
with plenty of space for lifting out or examining the cells. 


QUESTIONS AND ANSWERS ON CHATTER XXVII 

Question.—How are electric lamps classified? 

Answer.—As incandescent, arc, mercury vapor, and vacuum tube, 
which, with their variations, include the total field. 

Question.—What are the two most prominent types of lamps in 
use? 

Answer.—The incandescent with carbon filament, and the arc of 
the enclosed and the open type. 

Question.—What are the features of importance in the so-called 
flaming-arc lamp? 

Answer.—The use of an impregnated and cored carbon and the 
greater extension of the arc so as to give greater illumination. 

Question.—How is the modern lamp-filament made? 

Answer.—By the carbonization of a fine thread of cellulose, to 
which are attached platinum leading-in wires sealed in a glass stem. 

Question.—How are lamps rated? 

Answer.—By the watts or power consumed per candle-power. 


474 


QUESTIONS AND ANSWERS 


Question.—Why is platinum employed as leading-in wires? 

Answer.—Because the platinum expands and contracts at the 
same rate as the glass, and thus preserves the vacuum. 

Question.—What are the three elements to consider in lamps? 

Answer.—The cost, durability, and efficiency. 

Question-.—What is the difference between old lamps in service 
and new? 

Answer.—New lamps take less watts per candle-power than old 
ones. The older a lamp the more watts consumed per candle-power; 
lienee old lamps are less efficient and more wasteful commercially 
than new. 

Question.—How does the light of an arc-lamp compare with that 
of an incandescent lamp from the standpoint of efficiency and candle- 
power ? 

Answer.—An incandescent lamp takes about 3 to 3.5 watts per 
candle-power; therefore 1,000 candle-power obtained in this manner 
means a consumption of from 3,000 to 3,500 watts. An arc-lamp 
takes about 600 watts to deliver about 1,200 candle-power, or \ watt, 
or even less, per candle-power, depending upon the type of lamp. 
On this basis 1,000 candle-power by incandescent means at least 3,000 
watts consumed; by arc it means about 500 watts consumed. 

Question.—What is a Nernst lamp? 

Answer.—A lamp in which a piece of rare oxide is raised to in¬ 
candescence by means of a current. 

Question.—Wherein does a Nernst lamp possess advantages over 
the carbon filament? 

Answer.—In the fact that it can be safely raised to a higher tem¬ 
perature; also in the fact that no vacuum is necessary. 

Question.—What is an open arc? 

Answer.—An arc-lamp whose carbons burn in the open air. 

Question.—How are open-arc lamps connected up? 

Answer.—Generally as two in series on a 110- or 115-volt line. 

Question.—How are they connected on high-tension arc-lines? 

Answer.—In series throughout the system. An allowance of 
about 50 volts per lamp is made, which would mean at least forty 
open arcs in series on a 2,000-volt system. 


. QUESTIONS AND ANSWERS 


475 


Question. What are the features of the flaming-arc lamp? 

Answer. It produces a more efficient light than other arcs; it 
throws off deleterious gases; its carbons must be renewed every ten 
or fifteen hours;. its carbons are set at an angle to each other; the 
flame gives out light as well as the tips. 

Question.—What are the features of the enclosed-arc lamp? 

Answer.—It will burn 100 to 150 hours without attention or 
carbon-renewals; it takes more power than an open arc; its carbons 
last because the oxygen in the small globe surrounding the tips is 
consumed, and a valve prevents more air from entering freely. 

Question.—What defects appear in the enclosed arc? 

Answer.—The deposits on the inner globe cut down the light, and 
the separation of the carbons calls for a higher pressure than the open 
arc, a pressure of from 80 to 100 volts being required. This means 
only one lamp on a 110- or 115-volt line, and power wasted in the resist¬ 
ance necessary to limit the current. 

Question.—What is a mercury-vapor lamp? 

Answer.—A lamp formed by a tube with terminal electrodes, 
and containing a small quantity of mercury. By tilting the tube the 
mercury connects the electrodes, vaporizes, and forms a band of daz¬ 
zling light. 

Question.—What are its features in practice? 

Answer.—The production of a form of light without any red rays, 
a high efficiency, an automatic device for tilting it to start the arc. 

Question.—What is a vacuum-tube system of lighting? 

Answer.—At present it means a long tube of 50, 100, or 150 feet, 
containing a gas which, when affected by a high-pressure alternating 
current, produces commercial lighting effects. • It originally repre¬ 
sented a tube containing a vacuum, with electrodes by which the 
residuum of air caused illumination by molecular bombardment. 

Question.—What are its features? 

Answer.—An efficiency claimed to be that of the incandescent 
lamp, no deterioration of any consequence, ready installation, no 
glare, but a uniform glow. 

Question—What are the sources of power employed for electric 
lighting ? 

Answer.—Steam, gas, oil, water, and in some instances the sun 
or the wind. 


476 


QUESTIONS AND ANSWERS 


Question.—What are the elements of an electric-light plant? 

Answer.—The boiler and its accessories, the engine or turbine, 
the switchboard, and the circuits inside and outside used lor distribu¬ 
tion and transmission. 

Question.—What is a private plant, a central station, and a power¬ 
house ? 

Answer.—A private plant supplies current to a building or buildings 
and grounds, without any sale of current taking place or any municipal 
relationship being involved. A central station has as its primary 
purpose the sale of current under a franchise granted by the com¬ 
munity to be supplied. A power-house is generally representative 
of a plant supplying street-railway power to a trolley-line. It may 
be the distributing centre of a transmission-plant miles away. 

Question.—Into what sections may a plant of public or private 
utility be divided? 

Answer.—Into the steam section or power-developing element, 
the generating section, the transmitting and distributing section, and 
the illuminating and motive-power section. 

Question.—What is the great difficulty with our present method 
of light-production ? 

Answer.—The method of generating heat-waves in order to reach 
the light-waves required. 

Question.—What are the advantages, in an economic sense, of 
a water-power source instead of steam? 

Answer.—The limited cost of the power, provided it can be de¬ 
pended upon throughout the year, and the high efficiency of the water¬ 
wheel. 

Question.—What is the economic disadvantage of a water-power 
plant? 

Answer.—The limited value of the water-power due to its great 
distance from the community, and the cost of transmission, even 
though the power is regular, eliminating the gain otherwise in evi¬ 
dence. 

Question.—What are the advantages of producer gas in electric- 
light plants? 

Answer.—The use of the fuel in such a manner that the electricity 
produced is cheaper than by means of direct combustion for steam. 
No boiler is required, but a gas-producing plant, which distills the 


QUESTIONS AND ANSWERS 


477 


coal or other fuel, and the gas thus obtained is exploded in a gas- 
engine. Instead of heat and steam-power, use is made of gas and 
the explosive force latent when mixed with air. 

Question.—What is the drift of engineering practice in the lighting 
field ? 

Answer.—The production of cheaper power, in order to not only 
cheapen the cost of light, but increase the quantity in use per capita. 

Question.—What is the tendency in scientific light-making? 

Answer.—To attempt the production of light that possesses no 
preliminary heat-waves, in order to gain an efficiency that will in¬ 
crease the amount of light obtainable from a given power-consumption 
many fold. Where an incandescent lamp wastes 97 per cent, in heat, 
and gives out only 3 per cent, in light, the elimination of the heat- 
element would mean theoretically 33 X16, or 528 candle-power instead 
of only 16 candle-power for a watt consumption of 50. 
























■ 





















































































































































































INDEX. 

* For Index to Electrical Section, see page 485. 


A 

Acceleration of steam in nozles, 141. 
Actual efficiency, 181. 

Adiabatic expansion of steam, 171. 
Air- and circulating-pump, 126. 
Air-compressors, 385-389. 

Air for furnaces, 82, 83. 

Air, hot, for furnaces, 83. 

Air-pumps, 126, 127. 

American Company’s compound en¬ 
gine, 297. 

Ammonia, charging and starting, 370. 
Ammonia-compressor, 356. 
Ammonia-condensers, 361-363. 
Ammonia-cylinders, 359-361. 
Ammonia-plant, operation of, 364. 
Angle of connecting-rod, 231. 
Anhydrous ammonia, 349. 

Automatic elevator-governor, 377. 
Available heat, exhaust, 175. 
Available heat, steam, 175. 

Avery turbine, 317, 318. 

B 

Back pressure, 182. 

Balanced valves, 239, 240. 
Blowing-engine, 388. 

Boiler, Babcock & Wilcox, 59. 
Boiler-braces, 71, 72. 

Boiler, Cahall, 56. 

Boiler-chimney and its work, 74-85. 
Boiler, cylinder, 49. 

Boiler, cylinder tubular, 50-52. 

Boiler, double-flue, 50. 

Boiler, down-draught, 54. 


Boiler, duplex, 56. 

Boiler, Du Temple, 55. 
Boiler-furnaces, 31-48. 

Boiler, Galloway, 50. 

Boiler, heating and grate-surface of, 62. 
Boiler, Herreshoff, 54. 

Boiler horse-power, 61, 62, 184. 
Boiler-joints, 68-72. 

Boiler, marine, 33. 

Boiler, Robb-Mumford, 53. 
Boiler-setting, 51, 52. 

Boiler, Sterling, 57, 58. 

Boiler, Stevens, 49. 

Boiler, strength of, 67-73. 

Boiler, Thornycroft, 54. 

Boiler, vertical, 60. 

Boiler, Wood, 55. 

Boiler, Worthington, 41. 

Boilers, 41, 49-61. 

Boiling in vacuo, 28-30. 

Boiling-point of pure water, 26. 
Boiling-point of solutions, 27. 

Burners, oil, steam, and air, 46-48. 

C 

Cable-elevator, 372. 

Charging ammonia-plant, 370. 
Chimney-draught, 81-83. 

Chimneys, 75-80. 

Chimneys, steel and brick, 79. 

Coal, progress in saving, 22. 
Combustion, 34, 35. 

Compound engines, 292-307. 
Compression, 176, 182, 274. 
Compression and admission-lines, 204. 

479 


480 


INDEX 


Compression, excessive, 183. 
Compressors, air, 385-389. 
Condensation, initial, 208, 292. 
Condenser, siphon, 119, 120. 
Condenser-surface, 123-125. 
Condensers, 118-125. 

Condensers, ejector, 121. 

Condensers, jet, 121. 

Connecting-rod angle, 231. 
Cooling-towers, 127, 128. 

Corliss engine, 267-270, 289. 

Corliss valve-gear, 270-279. 

Cost of power, 390-392. 

Cost of superheating, 150. 

Critical temperature, 133. 

Curtiss steam-turbine, 332. 

Curves of nozles, 144. 

Cut-off, economical point of, 188. 
Cut-off, point of, 274, 275. 
Cylinder-condensation, 155, 173, 292. 
Cylinder dimensions, 209, 222. 
Cylinder ratios, 210. 

D 

Dashpot-governor, 284. 

Dashpots, 285, 286. 

De Laval turbine, 320-323. 

Denys Papin, 16. 

Details of elevator-operation, 379. 
Diagram, ammonia-compression, 363. 
Diagram, chimney-draught, 75. 
Diagram, compression and expansion 
of air, 384. 

Diagram, ideal and actual curves, 187. 
Diagram of economical cut-off, 188. 
Diagram of refrigeration, 354. 

Diagram of steam-generation, 131. 
Diagram of steam used, 201, 202. 
Diagram, pressures and temperatures, 
310. 

Diagram, turbine efficiency, 322. 
Diagram, turbine pressure, 332. 
Diagram, two-stage compression, 384. 
Diagrams, efficiency, 302, 303. 


Diagrams, indicator, 299-301. 
Diagrams, operating expenses, 392. 
Diagrams, receiver, 304, 305. 
Diagrams, slide-valve, 247, 248. 
Diverging-nozles, 142. 

Don4s for engineers and firemen, 401. 
Dow turbine, 324. 

Draught-gauge, 76. 

Draught-pressure in chimneys, 75, 76. 
Dryness of steam, x-, 143, 144. 

Dry steam, 131, 144. 

D slide-valve, 233-250. 

Duplex compound engine, 298, 299. 
Duplex cross compound Corliss, 14. 
Duplex-piston engine, 316. 

Duty-test, triple-expansion engine, 
309. 

E 

Eccentrics, shifting, 282, 283. 
Economical point of cut-off, 188. 
Economical suggestions in the use of 
steam for power, 394-399. 

Economy in heating feed-water, 84. 
Economy in high-speed engine, 177. 
Economy in refrigeration, 365. 
Economy of fuel, 22. 

Efficiency, actual, 1S1. 

Efficiency diagrams, 302, 303. 
Efficiency, engine-, ISO. 

Efficiency of heat-engine, 151. 
Efficiency of oil-fuel, 45. 
Efficiency-test, 309. 

Efficiency, turbine-, 322. 

Elevator and its work, 372-389. 
Elevator pilot-valves, 376. 
Elevator-plant, 375. 

Elevator-ramp, 380. 

Elevator safety-devices, 378. 

Elevator worm-gear, 381. 

Energy of steam, 145. 

Engine, Ball Engine Company, 264. 
Engine connecting-rods, 216, 227. 
Engine, Corliss, 267-270. 

Engine cross-head, 215, 224-226. 


INDEX 


481 


Engine details, 208-231. 
Engine-economy, 293. 

Engine fly-wheel, 222, 229. 

Engine, knocking and other noises, 401. 
Engine main bearings, 220, 227. 
Engine-piston, 213, 223-225. 

Engine, Porter-Allen, 262. 

Engine, rotary, 258, 343. 

Engine, Westinghouse, 300. 

Engines, compound, 292-307. 

Engines, right- and left-hand, 291. 
Engines, three-cylinder, 258. 

Engineer and his duties, 400-403. 
Eolipile, 15. 

Erratic admission-lines, 201. 

Escalator, 381. 

Evaporation factor, 116. 

Evaporation of water, 27, 28. 
Excessive compression, 183. 
Exhaust-lap change, 239. 
Exhaust-lines, erratic, 207. 
Expanding-nozle, 143, 144. 

Expansion, rule, 178. 

Exponent of expansion, 171. 

F 

Factors of evaporation, 117. 

Faulty valve-setting lines, 206. 
Feed-pipe, 67. 

Feed-water heaters, 86-93. 
Feed-water, heating, 84, 85. 

Fitchburg governor, 283. 

Floating valve-gear, 257. 

Flow of steam through orifices and 
nozles, 140. 

Flow of steam through pipes, 145. 
Fly-ball governors, 280, 281. 
Fly-wheels, 222, 230. 

Forced draught, 80, 82. 

Friction of steam, 146. 

Fuel, cost of, 34. 

Fuel for superheating, 155. 

Fuels, 31-35. 

Furnace-blowers, 81, 82. 

Fusible plug, 67. 


G 

Gain by high pressure, 185. 

Gases in chimney, 35. 

Gauge, pressure-, 66. 

Gauge, water-, 63, 65. 

Generation of steam, 31-48. 
Governor, turbine-, 331. 

Governors and dashpots, 279. 
Grate-bars, 36. 

Grates, traveling, 39, 40. 

Gridiron valves, 245, 246. 

H 

Harrisburg engine, 294. 

Heater, Berryman, 88. 

Heater, filter, 90. 

Heater, Green, 92. 

Heater, Hoppes, 91. 

Heater, multicoil, 86. 

Heater, open, 87. 

Heater, Wainwright-Cookson, 89. 
Heating power of fuels, 43. 

High-lift elevator, 375. 
High-pressure, gain, 186. 
High-pressure steam, 184. 
Horizontal-plunger elevator, 376. 
Hornblower’s engine, 19. 

Horse-power, 145. 

Horse-power from indicator-card, 200. 
Horse-power rating of boilers, 61, 62. 

I 

Ideal efficiency, 151. 

Illustrated superheaters, 160-170. 
Incrustation and remedy, 111-116. 
Indicator and its work, 190-207. 
Indicator-cards, 195, 201, 299, 301. 
Indicator-connections, 192-194. 
Indicator-kinks, 203-207. 
Indicator-measurement, 195. 
Indicators of boiler-control, 63. 

Initial condensation, 208. 
Injector-efficiency, 98. 


482 


INDEX 


Injector, Korting, and exhaust, 97. 
Injector, Little Giant, 96. 

Injector, Lunkenheimer, 96. 

Injector, Metropolitan, 97. 

Injector, Penberthy, 95. 

Injectors and steam-pump, 94-110. 

K 

Kinks in indicator-cards, 203-207. 
Knocking in the engine, 401. 

L 

Lane & Bodley governor, 281. 

Lap and lead, 237, 238. 

Lap, lead, and exhaust, 289. 

Latent heat of water, 132. 
Leakage-waste, 179. 

Link valve-gear, 253, 254. 

Loss in expansion, 186. 

M 

Marshall valve-gear, 255. 

Mean forward pressure, 173. 
Measurement, indicator-, 195. 
Measurement of steam, 169. 
Mechanical refrigeration, 348. 
Mechanical stokers, 37-42. 

Minnesota engines, 315. 

Montana engines, 311-313. 

Multiple expansion, 310, 311. 

N 

Natural gas fuel, 33, 34. 

Newcomen’s engine, 17. 

Nozles, steam-, 141, 142. 

O 

Object of superheating, 149. 
Oil-burners, 46-48. 

Oil-fuel, 43-45. 

Oscillating valve, 244. 

“Over” and “under run” engines, 235. 


P 

Parson’s turbine, 325-330. 
Petroleum-burners, 46-48. 
Petroleum-fuel, 33, 43-46. 

Pilot-valve, 331. 

Piston- and crank-stroke, 231. 
Piston-valves, 251, 252. 

Planimeter, 196-198. 

Pointers on refrigeration, 364. 
Port-opening, 236. 

Porter-Alien governor, 280. 
Pressure-gauge, 66. 

Progress, diagram of, 22. 

Progress in efficiency, 22. 
Proportions, steam-engine, 208-223. 
Pump, Blake, 107, 108. 

Pump, Cameron, 103. 

Pump, Deane, 101, 109. 

Pump, Guild & Garrison, 106, 107. 
Pump, Knowles, 100. 

Pump-lift, 99. 

Pump, McGowan, 104. 
Pump-proportions, 99. 
Pump-strainer, 109. 

Pump valve-gear, 102. 

Pump, Worthington, 101. 
Purification of feed-water, 111. 
Purifying apparatus, 113-116. 

Q 

Quality of steam, x, 144. 

Questions and Answers, 403-415. 

R 

Rateau turbine, 339, 340. 

Ratio of expansion, 186. 

Receivers, 304-306. 
Recording-gauge, 66. 
Reducing-wheel, 190, 191. 
Refrigerating-plant, 358. 
Refrigeration-engineering, 348-371. 
Refrigeration stages, 357. 
Reheating, 306, 307. 


INDEX 


483 


Reheating steam in receivers, 150. 
Release-lines, 206. 

S 

Safety-valv«e, 63-65. 

Sale of steam, 170. 

Salt-evaporating pan, 28. 

Saturated steam, 131. 

Saving by superheat, 154. 

Scottdale governor, 282. 

Separators, oil-, 126. 

Setting Corliss valve-gear, 286. 
Shifting eccentrics, 282. 

Simple valve-gear, 234. 

Slide-valve and gear, 233-266. 
Slide-valves, balanced, 240. 
Slide-valves, double-ported, 241. 
Slide-valves, gridiron, 245, 246. 
Slide-valves, independent cut-off, 241. 
Slide-valves, riding-cover, 240. 

Specific heat of steam, 132, 154, 
158. 

Specific heat of water, 132. 

Steam above atmospheric pressure, 

130. 

Steam and its properties, 24. 

Steam at 1,000 pounds pressure, 293. 
Steam consumption, 302, 303. 
Steam-engine proportions, 208, 223. 
Steam-exhaust for heating, 399. 
Steam-gun, 18. 

Steam-jets and -orifices, 140. 
Steam-lines, 205. 

Steam-plant, starting, 343. 
Steam-pump, 98-110. 

Steam-tables, 135-139. 
Steam-turbines, 317-347. 

Steam used from diagram, 201, 202. 
Steam-waste, leakage of, 179. 
Steaming power of boilers, 49-60. 
Stokers, 37-42. 

Sugar-evaporating plant, 29. 
Suggestions for economical steam- 
generation, 394-399. 


Superheat-economy, 147. 

Superheated steam, 131, 147-170. 

Superheaters, 159-170. 

Sweet governor, 283. 

T 

Table I. Boiling below atmospheric 
pressure, 25. 

Table II. Elastic force of vapor, 25. 

Table III. Boiling-point of pure 
water, 26. 

Table IV. Heat required for evapora¬ 
tion, 27. 

Table V. Fuel values, 32. 

Table VI. Heating and grate-sur¬ 
face, 62. 

Table VII. Pressures and areas, safe¬ 
ty-valves, 64. 

Table VIII. Proportions, boiler-joints, 
69. 

Table IX. Safe pressures, boilers, 70. 

Table X. Stays for boilers, 73. 

Table XI. Draught pressures, chim¬ 
ney-, 76. 

Table XII. Size and height of chim¬ 
neys, 77. 

Table XIII. Heat-saving in feed- 
water, 84. 

Table XIV. Feed-water heaters, 85. 

Table XV. Injector-discharge, 95. 

Table XVI. Pump-lift height, 99. 

Table XVII. Causes of incrustation, 

112 . 

Table XVIII. Factors of evapora¬ 
tion, 117. 

Table XIX. Water for condensing, 
123. 

Table XX. Properties of steam, 135. 

Table XXI. Steam-jet velocities, 
144. 

Table XXII. Flow of steam through 
pipes, 146. 

Table XXIII. Specific volumes, super¬ 
heat, 152. 


484 


INDEX 


Table XXIV. Steam-consumption, 
superheat, 153. 

Table XXV. Total heat of steam, 
159. 

Table XXVI. Real cut-off, 172. 

Table XXVII. Mean forward pres¬ 
sure, 174. 

Table XXVIII. Terminal pressure, 
175. 

Table XXIX. Heat-efficiency, 181. 

Table XXX. Cylinder dimensions, 

222 . 

Table XXXI. Cylinder dimensions, 
223. 

Table XXXII. Fly-wheel speeds, 
230. 

Table XXXIII. Effect of changing 
lap, travel, and angular advance, 
238. 

Table XXXIV. Lap, lead, exhaust, 
289. 

Table XXXV. Loss by cylinder-con¬ 
densation, 292. 

Table XXXVI. Water-consumption 
in compound and single-cylinder 
engines, 293. 

Table XXXVII. Cylinder-propor¬ 
tions, 294. 

Table XXXVIII. Water-consump¬ 
tion in triple-expansion engines, 
308. 

Table XXXIX. Tests Parson’s tur¬ 
bine, 330. 

Table XL. Properties of ammonia, 
351. 

Table XLI. Cost of power-plants, 
390. 

Table XLII. Cost of steam horse¬ 
power, 391. 

Table XLIII. Operating expenses, 
steam, 392. 

Temperature and pressures, 310. 

Test, triple-expansion engine-, 309. 

Theoretical efficiency, 180. 

Time for starting engines, 344, 346. 


Trials of fuels, 44, 45. 

Triple and quadruple engines, 308- 
316. 

Triple valve-gear, 259. 

Turbine, Curtiss, 333-339. 

Turbine, De Laval, 320-323. 

Turbine, Dow, 324. 

Turbine-governor, 331. 

Turbine-nozles and -blades, 335, 337. 
Turbine, Parson’s, 325-330. 

Turbine, Rateau, 339, 340. 
Turbine-step, 339. 

Turbine, Wilkinson, 325. 

Turbine, Zoelly, 341, 342. 

Turbines, steam-, 317-347. 

Types of boilers, 41, 49-61. 

Types of superheaters, 160-168. 

U 

“Under” and “over run” engines, 
235. 

V 

Vacuum-boiling, 28. 

Vacuum-dashpot, 285. 
Vacuum-installation, 128. 
Vacuum-pan, 28. 

Vacuum-pump, 126. 

Valve-gear, 234, 253-266. 

Valve-gear, Corliss, 270-279, 286. 
Valve-gear, floating, 257. 

Valve-gear, Joy’s, 260. 

Valve-gear, reversing, 257. 

Valve-gear, triple-expansion, 259. 
Valve positions, 235-239. 

Valves and compound cylinders, 295- 
297. 

Valves, balanced, 239, 240. 

Valves, double-ported, 241, 270. 
Valves, piston-, 251, 252. 

Valves with riding-cover, 240. 
Vauclain cylinders, 295, 296. 

Velocity of steam, 94, 95, 140, 143. 


INDEX 


485 


W 

Walschaert valve-gear, 256. 

Warship engines, 311-315. 

Waste in steam-making, 157. 

W ater-consumption, triple-expansion, 
308. 

Water-cooling towers, 177. 
Water-gauge, 63, 65. 

Water required for condensing, 122. 
Water-still, 28. 

Water used per horse-power hour, 199. 
Watertown governor, 280. 

Watts engine, 17. 


Wavy expansion-lines, 204. 
Westinghouse engine, 300. 
Wet steam, 131. 

Wilkinson turbine, 325. 
Worm-gear elevator, 381. 

• * 

X 

X, dryness of steam, 143, 144. 

Z 

Zero and negative lap, 237. 
Zoelly turbine, 341, 342. 


INDEX TO ELECTRICAL SECTION 


A 

Active material, 452. 

Alternating and direct current, 419. 
Ammeter-connections, 445. 
Appliances of switchboard, 446. 
Arc-lamps, 425. 

Armature-balance, 442. 
Armature-coils burnt out, 437. 
Armature-drop, 427. 

Asphaltum paint, 453. 

B 

Back E. M. F. calculated, 439. 

Back E. M. F. of motor, 439. 

Back field, 427. 

Bars short-circuited, 432. 
Battery-room, 454. 

Branches, the, 444. 

Brush-pressure, 435. 

Brushes, heat in the, 436. 

Buckling of plates, 451. 

C 

Calculating back E. M. F., 439. 
Calculation of E. M. F., 421. 


Carbon filament, 455. 

Cause of heat in armature, 433. 
Central station, 461. 

Centres of distribution, 444. 
Circuit-breaker, the, 445. 

Circuits, classification of, 444. 
Classification of dynamos, 424. 

Closed arcs, 425. 

Coils, radiating surface of, 435. 
Collector-rings and commutator, 420. 
Commutator, 431. 

Commutator and collector-rings, 420. 
Commutator, heat in the, 436. 
Commutator, use of, 422. 
Compensating winding, 429. 
Compound-wound dynamo, regula¬ 
tion with a, 428. 

Cost and durability of lamps, 458. 
Current-carrying parts, radiation of, 
435. 

Currents, parasitical, 436. 

D 

Depreciation in gas electric plants, 466. 
Direct and alternating current, 419. 
Distilling coal, 466. 


48G 

Distribution, centres of, 444. 

Drop in armature, 427. 

Durability of lamps, 458. 

Dynamo fails to generate, 432. 
Dynamo, operation of the, 419. 
Dynamo-regulation, 423. 

Dynamos, classification of, 424. 

E 

Efficiency of cells, 454. 

Efficiency of plants, 461. 

Electric gas-engine plants, 466. 
Electric lamps, 456. 

Electric-light equipments, 461. 
Electric plants, steam, 461. 

Electrical efficiency, 439. 
Electromotive force, generation of,420. 
Elements of a switchboard, 446. 
Enclosed arc, the, 459. 

Equipments, electric-light, 461. 

F 

Failure to generate, dynamo’s, 432. 
Faults, testing a dynamo for, 430. 
Faure plate, the, 449. 

Feeders, 444. 

Field of generator, 422. 

Filament, the carbon, 455. 

Flaming arc, the, 460. 

G 

Gas electric plants, 466. 

Gas-engine plants, 466. 

Gas plants, producer-, 466. 
Generating electromotive force, 420. 
Generator-field, 422. 

Ground-detector, the, 447. 

Grounded armature-coils, 440. 
Grounds, 450. 

H 

Heat in the commutator and brushes, 
436. 

Humming in motors, 442. 
Hydro-electric plants, 466. 


INDEX 

I 

Incandescent lamp, the, 455. 

J 

Jacobi’s principles, 437. 

L 

Lamps, cost of, 458. 

Lamps, durability of, 458. 
Lamps, electric, 456. 
Lightning-arrester, the, 448. 
Lines of force, 421. 

M 

Magnetic fringe, 432. 
Manufacturer’s guarantee, 465. 
Mercury vapor-lamp, 462. 
Motor, sparking in the, 440. 
Motor, too low speed of, 437. 
Motors, humming in, 442. 
Motors in service, 438. 

Motors, no'ses in, 442. 


Nernst lamp, the, 457. 

No field to motor, 440. 

Noises in motors, 442. 

O 

Old lamps, 458. 

Open arc, candle-power, 460. 
Open arcs, 425. 

Operation of the dynamo, 419. 

P 

Paint, asphaltum, 453. 

Panel board, 444. 

Parasitical currents, 436. 

Parts of switchboard, 441. 
Pasted plate, 452. 

Plante plate, the, 449. 




INDEX 


487 


Plants, efficiency of, 461. 

Plants, water-power, 463. 

Plates of storage-battery, 449. 

Poles alike, 433. 

Power-house, 461. 

Private plant, 461. 

Producer-gas plants, 466. 

Pure lead plate, 452. 

R 

Radiating surface of coils, 435. 
Regulating the dynamo, 423. 
Regulation with a compound-wound 
dynamo, 428. 

Regulation with a series-wound dy¬ 
namo, 425. 

Regulation with a shunt-wound dy¬ 
namo, 426. 

8 

Saving with enclosed arc, 459. 
Series-wound dynamo, regulation with 
a, 425. 

Shunt-wound dynamo, .lion with 
a, 426. 

Similar poles in a dynamo, 433. 
Sparking, 431. 

Sparking in the motor, 440. 

Steam electric plants, 461. 
Storage-batteries, 450 


Sulphating of plates, 451. 

Surface of coils, 438. • 

Switchboard, appliances of, 446. 
Switchboard, the, 441. 

T 

Testing, 430. 

Testing a dynamo for faults, 430. 

The dynamo, 419. 

The incandescent lamp, 455. 

The open arc, 460. 

Three equipments, 461. 

Troubles with plates, 451. 

Turbine, 463. 

Types of motors in service, 438. 

Types of storage-batteries, 450. 

U 

Use of the commutator, 422. 

V 

Vacuum-tube lamp, 462. 

Variable source of power, 463. 
Voltmeter-connections, 445. 

W 

Water-power plants, 463. 

Winding, compensating, 429. 


* - » 




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SUBJECT INDEX 


PAGE 

Accidents. 18 

Air Brakes.17, 19 

Arithmetics. 20 

Automobiles. 3 

Balloons. 3 

Bevel Gears. 14 

Boilers. 22 

Brazing. 3 

Cams. 15 

Car Charts. 4 

Change Gear. 14 

Charts.3, 4, 22 

Chemistry. 23 

Coal Mining. 23 

Coke. 4 

Compressed Air..• • • • 5 

Concrete. 5 

Cyclopedia.4, 20 

Dictionaries. 7 

Dies. 7 

Drawing.8, 24 

Drop Forging. 7 

Dynamo.9, 10, 11 

Electricity.9, 10, 11, 12 

Engines and Boilers. 22 

Factory Management. 12 

Flying Machines. 3 

Fuel. 13 

Gas Manufacturing. 14 

Gas Engines.13, 14 

Gears. 14 

Heating, Electric. 9 

Hot Water Heating. 27 

Horse-Power Chart. 4 

Hydraulics. 15 

Ice Making. 15 

India Rubber. 25 

Interchangeable Manufacturing. 20 

Inventions. 15 

Knots. 15 

Lathe Work. 16 

Lighting (Electric). 9 

Link Motion. 17 

Liquid Air.. . . . 16 

Locomotive Boilers. 18 

Locomotive Engineering.17, 18, 19 

Machinist’s Books.20, 21, 22 


PAGE 

Manual Training. 22 

Marine Engines. 22 

Marine Steam Turbines.. . 29 

Mechanical Movements.20, 21 

Metal Turning. 16 

Milling Machines. 21 

Mining.22, 23 

Oil Engines. 13 

Patents. 15 

Pattern Making. 23 

Perfumery. 23 

Pipes. 28 

Plumbing . 24 

Producer Gas.... 13 

Punches. 7 

Railroad Accidents. 18 

Receipt Book.23, 25 

Refrigeration. 15 

Rope Work. 15 

Rubber Stamps. 25 

Saws. 26 

Sheet Metal Working. 7 

Shop Tools. 21 

Shop Construction. 20 

Shop Management. 20 

Sketching Paper. 8 

Smoke Prevention. 13 

Soldering. 3 

Splices. 15 

Steam Engineering.26, 27 

Steam Heating. 27 

Steam Pipes. 28 

Steel. 2S 

Superheated Steam. 17 

Switchboards.9, 11 

Tapers. 16 

Telephone. 12 

Threads. 22 

Tools. 20, 22 

Turbines. 29 

Ventilation. 27 

Valve Gear. 19 

Valve Setting. 17 

Walschaert Valve Gear. 19 

Watchmaking. 29 

Wiring.9, 11, 12 


Wireless Telephones and Telegraphy.... 12 


ANY OF THESE BOOKS PROMPTLY SENT PREPAID TO ANY ADDRESS IN 

THE WORLD ON RECEIPT OF PRICE. 

to Remit .—By Postal Money Order, Express Money Order, Bank Draft 

or Registered Letter. 






































































































CATALOGUE OF GOOD, PRACTICAL BOOKS 


AUTOMOBILE 


THE MODERN GASOLINE AUTOMOBILE—ITS DESIGN, CONSTRUCTION, 
MAINTENANCE AND REPAIR. By Victor W. Page, M. E. 

The latest and most complete treatise on the Gasoline Automobile ever issued. Written 
in simple language by a recognized authority, familiar with every branch of the automobile 
industry. Tree from technical terms. Everything is explained so simply that anyone of 
average intelligence may gain a comprehensive knowledge of the gasoline automobile. 
1 he information is up-to-date and includes, in addition to an exposition of principles of 
construction and description of all types of automobiles and their components, valuable 
money-saving hints on the care and operation of motor cars propelled by internal combus¬ 
tion engines. Among some of the subjects treated might be mentioned: Torpedo and other 
symmetrical body forms designed to reduce air resistance; sleeve valve, rotary valve and 
other types of silent motors; increasing tendency to favor worm-gear power-transmission; 
universal application of magneto ignition; development of automobile electric-lighting 
systems; block motors; underslung chassis; application of practical self-starters; long stroke 
and offset cylinder motors; latest automatic lubrication systems; silent chains for valve 
operation and change-speed gearing; the use of front wheel brakes and many other detail 
refinements. 

By a careful study of the pages of this book one can gain practical knowledge of automobile 
construction that will save time, money and worry. The book tells you just what to do, how 
and when to do it. Nothing has been omitted, no detail has been slighted. Every part of 
the automobile, its equipment, accessories, tools, supplies, spare parts necessary, etc., have 
been discussed comprehensively. If you are or intend to become a motorist, or are in 
any way interested in the modern Gasoline Automobile, this is a book you cannot afford to 
be without. Nearly 600 6x9 pages—and more than 500 new and specially made detail il¬ 
lustrations. as well as many full page and double page plates, showing all parts of the 
automobile. Including nine large folding plates. Price.$2.50 

BALLOONS AND FLYING MACHINES 


MODEL BALLOONS AND FLYING MACHINES. WITH A SHORT ACCOUNT OF 
THE PROGRESS OF AVIATION. By J. H. Alexander. 

This book has been written with a view to assist those who desire to construct a model airship 
or flying machine. It contains five folding plates of working drawings, each sheet containing 
a different sized machine. Much instruction and amusement can be obtained from the making 
and flying of these models. 

A short account of the progress of aviation is included, which will render the book of greater 
interest. Several illustrations of full sized airship and flying machines of the latest types are 
scattered throughout the text. This practical work gives data, working drawings, and details 
which will assist materially those Interested in the problems of flight. 127 pages, 45 illustra¬ 
tions, 5 folding plates. Price.$1.50 

BRAZING AND SOLDERING 


BRAZING AND SOLDERING. By James F. Hobabt. 

The only book that shows you just how to handle any job of brazing or soldering that comes 
Llong; tells you what mixture to use, how to make a furnace if you need one. Full of 
valuable kinks. The fifth edition of this book has just been published, and to it much 
new matter and a large number of tested formulas for all kinds of solders and fluxes have 
been added. Illustrated.25 cents 


CHARTS 


MODERN SUBMARINE CHART—WITH 200 PARTS NUMBERED AND NAMED. 

A cross-section view, showing clearly and distinctly all the interior of a Submarine of the 
latest type. You get more information from this chart, about the construction and opera¬ 
tion of a Submarine, than in any other way. No details omitted—everything is accurate 
and to scale. It is absolutely correct in every detail, having been approved by Naval 
Engineers. All the machinery and devices fitted in a modern Submarine Boat are shown and 
to make the engraving more readily understood all the features are shown in operative form, 
with Officers and Men in the act of performing the duties assigned to them in service con¬ 
ditions. This CHART IS REALLY AN ENCYCLOPEDIA OF A SUBMARINE. It 
is educational and worth many times its cost. Mailed in a Tube for. 25 cents 


3 

















CATALOGUE OF GOOD, PRACTICAL BOOKS 


BOX CAR CHART. 

A chart showing the anatomy of a box car, having every part of the car numbered and its 
proper name given in a reference list. 20 cents 

GONDOLA CAR CHART. 

A chart showing the anatomy of a gondola car, having every part of the car numbered and 
its proper reference name given in a reference list. 20 cents 

PASSENGER CAR CHART. 

A chart showing the anatomy of a passenger car, having every part of the car numbered and 
its proper name given in a reference list. . . . .. 20 cents 

WESTINGHOUSE AIR-BRAKE CHARTS. 

Chart I.—Shows (in colors) the most modern Westinghouse High Speed and Signal Equip¬ 
ment used on Passenger Engines, Passenger Engine Tenders, and Passenger Cars. Chart 
II.—Shows (in colors) the Standard Westinghouse Equipment for Freight and Switch En¬ 
gines, Freight and Switch Engine Tenders, and Freight Cars. Price for the set . 50 cents 

TRACTIVE POWER CHART. 

A chart whereby you can find the tractive power or drawbar pull of any locomotive, without 
making a figure. Shows what cylinders are equal, how driving wheels and steam pressure 
affect the power. What sized engine you need to exert a given drawbar pull or anything 
you desire in this line. 50 cents 

HORSE POWER CHART. 

Shows the horse power of any stationary engine without calculation. No matter what the 
cylinder diameter of stroke; the steam pressure or cut-off; the revolutions, or whether con¬ 
densing or non-condensing, it’s all there. Easy to use, accurate, and saves time and calcu¬ 
lations. Especially useful to engineers and designers. ... 50 cents 

BOILER ROOM CHART. By Geo. L. Fowler. 

A Chart—size 14 x 28 inches—showing in isometric perspective the mechanisms belonging 
in a modern boiler room. Water tube boilers, ordinary grates and mechanical stokers, feed 
water heaters and pumps comprise the equipment. The various parts are shown broken or 
removed, so that the internal construction is fully illustrated. Each part is given a reference 
number, and these, with the corresponding name, are given in a glossary printed at the sides. 
This chart is really a dictionary of the boiler room—the names of more than 200 parts being 
given. It is educational—worth many times its cost. 25 cents 

CIVIL ENGINEERING 


HENLEY’S ENCYCLOPEDIA OF PRACTICAL ENGINEERING AND ALLIED 
TRADES. Edited by Joseph G. Horner, A. M. I. E. M. 

This set of five volumes contains about 2,500 pages w r ith thousands of illustrations, including 
diagrammatic and sectional drawings with full explanatory details. This work covers the 
entire practice of Civil and Mechanical Engineering. The best known experts in all branches 
of engineering have contributed to these volumes. The Cyclopedia is admirably well adapted 
to the needs of the beginner and the self-taught practical man, as well as the mechanical en¬ 
gineer, designer, draftsman, shop superintendent, foreman, and machinist. The work will be 
found a means of advancement to any progressive man. It is encyclopedic in scope, thorough 
and practical in its treatment of technical subjects, simple and clear in its descriptive matter, 
and without unnecessary technicalities or formulae. The articles are as brief as may be and 
yet give a reasonably clear and explicit statement of the subject, and are written by men who 
have had ample practical experience in the matters of which they write. It tells you all you 
want to know about engineering and tells it so simply, so clearly, so concisely, that^one cannot 
help but understand. As a work of reference it is w ithout a peer. $6.00 per single volume. 
For complete set of five volumes, price . $25.00 


COKE 


COKE—MODERN COKING PRACTICE; INCLUDING THE ANALYSIS OF 
MATERIALS AND PRODUCTS. By T. H. Byrom and J. E. Christopher. 

A handbook for those engaged in Coke manufacture and the recovery of By-products. Fully 
illustrated with folding plates. It has been the aim of the authors, in preparing this book, 
to produce one which shall be of use and benefit to those who are associated with, or inter¬ 
ested in, the modern developments of the industry. Contents: I. Introductory. II. Gen- 


4 

















CATALOGUE OF GOOD, PRACTICAL BOOKS 


eral Classification of Fuels. III. Coal Washing. IV. The Sampling and Valuation of Coal, 
Coke, etc. V. The Calorific Power of Coal and Coke. VI. Coke Ovens. VII. Coke Ovens, 
continued. VIII. Coke Ovens, continued. IX. Charging and Discharging of Coke Ovens, 
X. Cooling and Condensing Plant. XI. Gas Exhausters. XII. Composition and Analysis 
of Ammoniacal Liquor. XIII. Working-up of Ammoniacal Liquor. XIV. Treatment of 
Waste Gases from Sulphate Plants. XV. Valuation of Ammonium Sulphate. XVI. Direct 
Recovery of Ammonia from Coke Oven Gases. XVII. Surplus Gas from Coke Oven. Use¬ 
ful Tables. Very fully illustrated. Price.$3.50 net 

COMPRESSED AIR 


COMPRESSED AIR IN ALL ITS APPLICATIONS. By Gardner D. Hiscox. 

This is the most complete book on the subject of Air that has ever been issued, and its thirty- 
five chapters include about every phase of the subject one can think of. It may be called an 
encyclopedia of compressed air. It is written by an expert, who, in its 665 pages, has dealt 
with the subject in a comprehensive manner, no phase of it being omitted. Includes the 
physical properties of air from a vacuum to its highest pressure, its thermodynamics, com¬ 
pression, transmission and uses as a motive power; in the Operation of Stationary and Port¬ 
able Machinery, in Mining. Air Tools, Air Lifts, Pumping of Water. Acids, and Oils; the 
Air Blast for Cleaning and Painting, the Sand Blast and its Work, and the Numerous Appli¬ 
ances in which Compressed Air is a Most Convenient and Economical Transmitter of Power 
for Mechanical Work, Railway Propulsion, Refrigeration, and the Various Uses to which 
Compressed Air has been applied. Includes forty-four tables of the physical properties of 
air, its compression, expansion, and volumes required for various kinds of work, and a list of 
patents on compressed air from 1875 to date. Over 500 illustrations, 5th Edition, revised and 
enlarged. Cloth bound, $5.00. Half Morocco, price. . $6.50 

CONCRETE 


ORNAMENTAL CONCRETE WITHOUT MOLDS. By A. A. Houghton. 

The process for making ornamental concrete without molds has long been held as a secret, and 
now, for the first time, this process is given to the public. The book reveals the secret and is 
the only book published which explains a simple, practical method whereby the concrete worker 
is enabled, by employing wood and metal templates of different designs, to mold or model in 
concrete any Cornice, Archivolt, Column, Pedestal, Base Cap, Urn or Pier in a monolithic 
form—right upon the job. These may be molded in units or blocks, and then built up to suit the 
specifications demanded. This work is fully illustrated, with detailed engravings. Price $2.00 

CONCRETE FROM SAND MOLDS. By A. A. Houghton. 

A Practical Work treating on a process which has heretofore been held as a trade secret by 
the few who possessed it, and which will successfully mold every and any class of ornamental 
concrete work. The process of molding concrete with sand molds is of the utmost practical 
value possessing the manifold advantages of a low cost of molds, the ease and rapidity of 
operation perfect details to all ornamental designs, density, and increased strength of the 
concrete, perfect curing of the work without attention and the easy removal of the molds re¬ 
gardless of any undercutting the design may have. 192 pages. Fully illustrated. Price $2.00 


CONCRETE WALL FORMS. By A. A. Houghton. 

A new automatic wall clamp is illustrated with working drawings. Other types of wall 
forms, clamps, separators, etc., are also illustrated and explained.. 50 cents 


CONCRETE FLOORS AND SIDEWALKS. By A. A. Houghton. 

The molds for molding squares, hexagonal and many other styles of mosaic floor and side¬ 
walk blocks are fully illustrated and explained.50 cents 


PRACTICAL CONCRETE SILO CONSTRUCTION. By A. A. Houghton. 
Complete working drawings and specifications are given for several styles of concrete silos, 
with illustrations of molds for monolithic and block silos. The tables, data and information 
presented in this book are of the utmost value in planning and constructing all forms of concrete 
silos.'.50 cents 


MOLDING CONCRETE CHIMNEYS, SLATE AND ROOF TILES. By 

A A Houghton. 

The" manufacture of all types of concrete slate and roof tile is fully treated. Valuable data 
on all forms of reinforced concrete roofs are contained within its pages. 1 he construction of 
concrete chimneys by block and monolithic systems is fully illustrated and described. A 
number of ornamental designs of chimney construction with molds are shown in tins valu¬ 
able treatise.• • • • *. 50 cents 


5 
















CATALOGUE OF GOOD, PRACTICAL BOOKS 


MOLDING AND CURING ORNAMENTAL CONCRETE By A. A. Houghton. 

The proper proportions of cement and aggregates for various finishes, also the methods of 
thoroughly mixing and placing in the molds, are fully treated. An exhaustive treatise on this 
subject that every concrete worker will find of daily use and value.oO cents 

CONCRETE MONUMENTS, MAUSOLEUMS AND BURIAL VAULTS. By A. A. 

Houghton. _ . 

The molding of concrete monuments to imitate the most expensive cut stone is explained in 
this treatise, with working drawings of easily built molds. Cutting inscriptions and designs 
is also fully treated. .50 cents 

MOLDING CONCRETE BATH TUBS, AQUARIUMS AND NATATORIUMS. 

By A. A. Houghton. 

Simple molds and instruction are given for molding many styles of concrete bath tubs, 
swimming pools, etc. These molds are easily built and permit rapid and successful 
. .50 cents 

CONCRETE BRIDGES, CULVERTS AND SEWERS. By A. A. Houghton. 

A number of ornamental concrete bridges with illustrations of molds are given. A collapsible 
center or core for bridges, culverts and sewers is fully illustrated with detailed instructions for 
building ... . 50 cents 

CONSTRUCTING CONCRETE PORCHES. By A. A. Houghton. 

A number of designs with working drawings of molds are fully explained so any jne can easily 
construct different styles of ornamental concrete porches without the purchase of expensive 
molds.50 cents 

MOLDING CONCRETE FLOWER POTS, BOXES, JARDINIERES, ETC. By 

A. A. Houghton. 

The molds for producing many original designs of flower pots, urns, flower boxes, jardinieres, 
etc., are fully illustrated and explained, so the worker can easily construct and operate 
same. 50 cents 

MOLDING CONCRETE FOUNTAINS AND LAWN ORNAMENTS. By 

A. A. Houghton. 

The molding of a number of designs of lawn seats, curbing, hitching posts, pergolas, sun dials 
and other forms of ornamental concrete for the ornamentation of lawns and gardens, is 
fully illustrated and described. 50 cents 

CONCRETE FOR THE FARM AND SHOP. By A. A. Houghton. 

The molding of drain tile, tanks, cisterns, fence posts, stable floors, hog and poultry houses 
and all the purposes for which concrete is an invaluable aid to the farmer are numbered 
among the contents of this handy volume... 50 cents 

POPULAR HANDBOOK FOR CEMENT AND CONCRETE USERS. By Myron 
H. Lewis, 

This is a concise treatise of the principles and methods employed in the manufacture and use 
of cement in all classes of modern works. The author has brought together in this work all 
the salient matter of interest to the user of concrete and its many diversified products. The 
matter is presented in logical and systematic order, clearly written, fully illustrated and free 
from involved mathematics. Every tiling of value to the concrete user is given including kinds 
of cement employed in construction, concrete architecture, inspection and testing, water¬ 
proofing, coloring and painting, rules, tables, working, and cost data. The book comprises 
thirty-three chapters, as follows: 

Introductory. Kinds of Cements and How They are Made'. Properties, Testing and 
Requirements of Hydraulic Cement. Concrete and its Properties. Sand, Broken Stone and 
Gravel for Concrete. How to Proportion the Materials. How to Mix and Place Concrete. 
Forms for Concrete Construction. The Architectural and Artistic Possibilities of Concrete. 
Concrete Residences. Mortars, Plasters and Stucco and How to Use Them. The Artistic 
Treatment of Concrete Surfaces. Concrete Building Blocks. The Making of Ornamental 
Concrete. Concrete Pipes, Fences, Posts, Etc. Essential Features and Advantages of Reen¬ 
forced Concrete. How to Design Reenforced Concrete Beams, Slabs and Columns. Ex¬ 
planations of the Methods and Principles in Designing Reenforced Concrete Beams and 
Slabs. Systems of Reenforcement Employed. Reenforced Concrete in Factory and General 














CATALOGUE OF GOOD, PRACTICAL BOOKS 


Building Construction. Concrete in Foundation Work. Concrete Retaining Walls, Abut¬ 
ments, and Bulkheads Concrete Arches and Arch Bridges. Concrete Beam and Girder 
Bridges. Concrete in Sewerage and Drainage Works. Concrete Tanks, Dams and Reser- 
^} rs - Sidewalks, Curbs and Pavements. Concrete in Railroad Constructions. 

The Utility of Concrete on the Farm. The Waterproofing of Concrete Structure. Grout 
or Liquid Concrete and Its Use. Inspection of Concrete Work. Cost of Concrete Work. 
Some ol the special features of the book are: 1. The Attention Paid to the Artistic and 
Architectural Side of Concrete Work. 2. The Authoritative Treatment of the Problem 
of Waterproofing Concrete. 3. An Excellent Summary-of the Rules to be Followed in 
Concrete Construction. 4. The Valuable Cost Data and Useful Tables given. A valuable 
Addition to the Library of Every Cement and Concrete User. Price.$2.50 

WATERPROOFING CONCRETE. By Myron H. Lewis. 

Modern Methods of Waterproofing Concrete and Other Structures. A condensed statement 
of the Principles, Rules, and Precautions to be Observed in Waterproofing and Damp- 
proofing Structures and Structural Materials. Paper binding. Illustrated. Price. . 50 cents 


DICTIONARIES 


STANDARD ELECTRICAL DICTIONARY. By T. O’Conor Sloane. 

An indispensable work to all interested in electrical science. Suitable alike for the student 
and professional. A practical hand-book of reference containing definitions of about 5,000 
distinct words, terms and phrases. The definitions are terse and concise and include every 
term used in electrical science. Recently issued. An entirely new edition. Should be in 
the possession of all who desire to keep abreast with the progress of this branch of science. 
Complete, concise and convenient. 682 pages. 393 illustrations. Price .... $3.00 


DIES—METAL WORK 


DIES: THEIR CONSTRUCTION AND USE FOR THE MODERN WORKING OF 
SHEET METALS. By J. V. Woodworth. 

A most useful book, and one which should be in the hands of all engaged in the press working 
of metals; treating on the Designing, Constructing, and Use of Tools, Fixtures and Devices, 
together with the manner in which they should be used in the Power Press, for the cheap and 
rapid production of the great variety of sheet metal articles now in use. It is designed as a 
guide to the production of sheet metal parts at the minimum of cost with the maximum of 
output. The hardening and tempering of Press tools and the classes of work which may be 
produced to the best advantage by the use of dies in the power press are fully treated. Its 
505 illustrations show dies, press fixtures and sheet metal working devices, the descriptions 
of which are so clear and practical that all metal-working mechanics will be able to understand 
how to design, construct and use them. Many of the dies and press fixtures treated were 
either constructed by the author or under his supervision. Others were built by skilful 
mechanics and are in use in large sheet metal establishments and machine shops. Price $3.00 

PUNCHES, DIES AND TOOLS FOR MANUFACTURING IN PRESSES. By J. V. 

Woodworth. 

This work is a companion volume to the author’s elementary work entitled “Dies, Their 
Construction and Use.” It does not go into the details of die making to the extent of the 
author’s previous book, but gives a comprehensive review of the field of operations carried on 
by presses A large part of the information given has been drawn from the author’s personal 
experience It might well be termed an Encyclopedia of Die Making, Punch Making, Die 
Sinking Sheet Metal Working, and Making of Special Tools, Sub-presses, Devices and Mechani¬ 
cal Combinations for Punching, Cutting, Bending, Forming, Piercing, Drawing Compressing 
and Assembling Sheet Metal Parts, and also Articles of other Materials in Machine Tools. 
2d Edition. Price.. 


DROP FORGING, DIE SINKING AND MACHINE FORMING OF STEEL. By J. V. 

Woodworth. 

This is a practical treatise on Modern Shop Practice, Processes, Methods Machines, Tools, 
and Details, treating on the Hot and Cold Machine-Forming of Steel and Iron into Finished 
shapes - Together with Tools, Dies, and Machinery involved m the manufacture of Duplicate 


7 










CATALOGUE OF GOOD, PRACTICAL BOOKS 


Forgings and Interchangeable Hot and Oold Pressed Parts from Bar and Sheet Metal. 
This book fills a demand of long standing for information regarding drop forging, die-sinkmg 
and machine forming of steel and the shop practice involved, as it actually exists in the 
modern drop forging shop. The processes of die-sinking and force-mak ,n g, which are thor¬ 
oughly described and illustrated in this admirable work, are rarely tc oe found explained in 
such a clear and concise manner as is here set forth. The process of die-smking relates to 
the engraving or sinking of the female or lower dies, such as are used for drop forgings, hot 
and cold machine forging, swedging and the press working of metals. The process of force¬ 
making relates to the engraving or raising of the male or upper dies used in producing the 
lower dies for the press-forming and machine-forging of duplicate parts of metal. 

In addition to the arts above mentioned the book contains explicit information regarding 
the drop forging and hardening plants, designs, conditions, equipment, drop hammers, 
forging machines, etc., machine forging, hydraulic forging, autogenous welding and shop 
practice. The book contains eleven chapters, and the information contained in these chapters 
is just what will prove most valuable to the forged metal worker. All operations described 
in the work are thoroughly illustrated by means of perspective half-tones and outline sketches 
of the machinery employed. 300 detailed illustrations. Price. $2.50^ 


DRAWING—SKETCHING PAPER 


LINEAR PERSPECTIVE SELF-TAUGHT. By Herman T. C. Kraus. 

This work gives the theory and practice of linear perspective, as used in architectural, engi¬ 
neering, and mechanical drawings. Persons taking up the study of the subject by themselves 
will be able by the use of the instruction given to readily grasp the subject, and by reason¬ 
able practice become good perspective draftsmen. The arrangement of the book is good; 
the plate is on the left-hand, while the descriptive text follows on the opposite page, so as to 
be readily referred to. The drawings are on sufficiently large scale to show the work clearly 
and are plainly figured. The whole work makes a very complete course on perspective draw¬ 
ing, and will be found of great value to architects, civil and mechanical engineers, patent 
attorneys, art designers, engravers, and draftsmen. $2.50 

PRACTICAL PERSPECTIVE. By Richards and Colvin. 

Shows just how to make all kinds of mechanical drawings in the only practical perspective 
isometric. Makes everything plain so that any mechanic can understand a sketch or drawing 
in this way. Saves time in the drawing room, and mistakes in the shops. Contains practical 
examples of various classes of work. 3rd Edition. 50 cents 

SELF-TAUGHT MECHANICAL DRAWING AND ELEMENTARY MACHINE 
DESIGN. By F- L. Sylvester, M.E., Draftsman, with additions by Erik Oberg, 
associate editor of “Machinery.” 

This is a practical treatise on Mechanical Drawing and Machine Design, comprising the 
first principles of geometric and mechanical drawing, workshop mathematics, mechanics, 
strength of materials and the calculations and design of machine details. The author’s 
aim has been to adapt this treatise to the requirements of the practical mechanic and young 
draftsman and to present the matter in as clear and concise a manner as possible. To 
meet the demands of this class of students, practically all the important elements of machine 
design have been dealt with, and in addition algebraic formulas have been explained, and 
the elements of trigonometry treated in the manner best suited to the needs of the prac¬ 
tical man. The book is divided into 20 chapters, and in arranging the material, mechan¬ 
ical drawing, pure and simple, has been taken up first, as a thorough understanding of the 
principles of representing objects facilitates the further study of mechanical subjects. This 
is followed by the mathematics necessary for the solution of the problems in machine de¬ 
sign which are presented later, and a practical introduction to theoretical mechanics and 
the strength of materials. The various elements entering into machine design, such as cams, 
gears, sprocket wheels, cone pulleys, bolts, screws, couplings, clutches, shafting and fly¬ 
wheels have been treated in such a way as to make possible the use of the work as a text¬ 
book for a continuous course of study. It is easily comprehended and assimilated even by 
students of limited previous training. 330 pages, 215 engravings. Price. . . . $2.00 

A NEW SKETCHING PAPER. 

A new specially ruled paper to enable you to make sketches or drawings in isometric perspective 
without any figuring or fussing. It is being used for shop details as well as for assembly 
drawings, as it makes one sketch do the work of three, and no workman can help seeing just 
what is wanted. Pads of 40 sheets, 6x9 inches, 25 cents. Pads of 40 sheets, 9 x 12 inches. 
50 cents; 40 sheets, 12x18, Price. $1.00 


8 










CATALOGUE OF GOOD, PRACTICAL BOOKS 


ELECTRICITY 


ARITHMETIC OF ELECTRICITY. By Prof. T. O’Conor Sloane. 

A practical treatise on electrical calculations of all kinds reduced to a series of rules, all of the 
simplest forms, and involving only ordinary arithmetic; each rule illustrated by one or more 
practical problems, with detailed solution of each one. This book is classed among the most 
useful works published on the science of electricity covering as it does the mathematics of 
electricity in a manner that will attract the attention of‘those who are not familiar with alge¬ 
braical formulas. 20th Edition. 160 pages. Price.$1.00 

COMMUTATOR CONSTRUCTION. By Wm. Baxter, Jr. 

The business end of any dynamo or motor of the direct current type is the commutator. This 
book goes into the designing, building, and maintenance of commutators, shows how to locate 
troubles and how to remedy them; everyone who fusses with dynamos needs this. 35 cents 


DYNAMO BUILDING FOR AMATEURS, OR HOW TO CONSTRUCT A FIFTY-WATT 

DYNAMO. By Arthur J. Weed, Member of N. Y. Electrical Society. 

A practical treatise showing in detail the construction of a small dynamo or motor, the entire 
machine work of which can be done on a small foot lathe. Dimensioned working drawings 
are given for each piece of machine work and each operation is clearly described. This 
machine, when used as a dynamo, has an output of fifty watts; when used as a motor it will 
drive a small drill press or lathe. It can be used to drive a sewing machine on any and all 
ordinary work. The book is illustrated with more than sixty original engravings showing 
the actual construction of the different parts. Among the contents are chapters on 1. Fifty 
Watt Dynamo. 2. Side Bearing Rods. 3. Field Punchings. 4. Bearings. 5. Commu¬ 
tator. 6. Pulley. 7. Brush Holders. 8. Connection Board. 9. Armature Shaft. 10. 
Armature. 11. Armature Winding. 12. Field Winding. 13. Connecting and Starting. 
Price, paper, 50 cents. Cloth.$1.00 


ELECTRIC FURNACES AND THEIR INDUSTRIAL APPLICATIONS. By J. Wright 


This is a book which will prove of interest to many classes of people; the manufacturer who 
desires to know what product can be manufactured successfully in the electric furnace, the 
chemist who wishes to post himself on the electro-chemistry, and the student of science who 
merely looks into the subject from curiosity. The book is not so scientific as to be of use 
only to the technologist, nor so unscientific as to suit only the tyro in electro-chemistry; it 
is a practical treatise of what has been done, and of what is being done, both experimentally 
and commercially with the electric furnace. 

In important processes not only are the chemical equations given, but complete thermal data 
are set forth and both the efficiency of the furnace and the cost of the product are worked 
out thus giving the work a solid commercial value aside from its efficacy as a work of reference. 
The practical features of furnace building are given the space that the subject deserves. The 
forms and refractory materials used in the linings, the arrangement of the connections to the 
electrodes, and other important details are explained. 288 pages. New Revised Edition. 
Fully illustrated. Price.$3.00 


ELECTRIC LIGHTING AND HEATING POCKET BOOK. By Sydney F. Walker. 

This book puts in convenient form useful information regarding the apparatus which is likely 
to be attached to the mains of an electrical company. Tables of units and equivalents are 
included and useful electrical laws and formulas are stated. 

One section is devoted to dynamos, motors, transformers and accessory apparatus; another 
to accumulators, another to switchboards and related equipment, a fourth to a description 
of various systems of distribution, a fifth section to a discussion of instruments, both for 
nortable use and switchboards; another section deals with electric lamps of various types 
and accessory appliances, and the concluding section is given up to electric heating apparatus. 
In each section a large number of commercial types are described, frequent tables of dimen¬ 
sions being included. A great deal of detail information of each lme of apparatus is given 
and the illustrations shown give a good idea of the general appearance of the apparatus under 
discussion. The book also contains much valuable information for the central station engi¬ 
neer. 438 pages. 300 engravings. Bound in leather pocket book form. Price . $3.00 

ELECTRIC WIRING, DIAGRAMS AND SWITCHBOARDS. By Newton Harrison. 

\ thoroughly practical treatise covering the subject of Electric Wiring in aUL^i v b s?mS?fv 
including explanations and diagrams which are thproughly explicit^and^greatly simphfy 
the subiect Practical every-day problems in wiring are presented and the method of 
obtaining intelligent results clearly shown. Only arithmetic is used. Ohm s law is given 


9 










CATALOGUE OF GOOD, PRACTICAL BOOKS 


a simple explanation with reference to wiring for direct and alternating currents. The funda¬ 
mental principle of drop of potential in circuits is shown with its various applications. The 
simple circuit is developed with the position of mains, feeders and branches; their treat¬ 
ment as a part of a wiring plan and their employment in house-wiring clearly illustrated. 
Some simple facts about testing are included in connection with the wiring. Molding 
and conduit work are given careful consideration; and switchboards are systematically 
treated, built up and illustrated, showing the purpose they serve, for connection with the 
circuits, and to shunt and compound wound machines. The simple principles of switchboard 
construction, the development of the switchboard, the connections of the various instru¬ 
ments including the lightning arrester, are also plainly set forth. 

Alternating current wiring is treated, with explanations of the power factor, conditions 
calling for various sizes of wire and a simple way of obtaining the sizes for single-phase, two- 
phase and three-phase circuits. This is the only complete work issued showing and telling 
you what you should know about direct and alternating current wiring. It is a ready refer¬ 
ence. The work is free from advanced technicalities and mathematics, arithmetic being used 
throughout. It is in every respect a handy, well-written, instructive, comprehensive 
volume on wiring for the wireman, foreman, contractor, or electrician. 272 pages; 105 illus¬ 
trations. Price. .$1.50 

ELECTRIC TOY MAKING, DYNAMO BUILDING, AND ELECTRIC MOTOR CON¬ 
STRUCTION. By Prof. T. O’Conor Sloane. 

This work treats of the making at home of electrical toys, electrical apparatus, motors, dynamos 
and instruments in general, and is designed to bring within the reach of young and old the 
manufacture of genuine and useful electrical appliances. The work is especially designed for 
amateurs and young folks. 

Thousands of our young people are daily experimenting, and busily engaged in making electrical 
toys and apparatus of various kinds. The present work is just what is wanted to give the 
much needed information in a plain, practical manner, with illustrations to make easy the 
carrying out of the work. 19th Edition. Price.$1.00 

ELECTRICIAN’S HANDY BOOK. By Prof. T. O’Conor Sloane. 

This work of 768 pages is intended for the practical electrician who has to make things go. 
The entire field of electricity is covered within its pages. Among some of the subjects treated 
are: The Theory of the Electric Current and Circuit, Electro-Chemistry, Primary Batteries, 
Storage Batteries, Generation and Utilization of Electric Powers, Alternating Current, Arma¬ 
ture Winding, Dynamos and Motors, Motor Generators, Operation of the Central Station 
Switchboards, Safety Appliances, Distribution of Electric Light and Power, Street Mains, 
Transformers, Arc and Incandescent Lighting, Electric Measurements, Photometry, Electric 
Railways, Telephony, Bell-Wiring, Electro-Plating, Electric Heating, Y/ireless Telegraphy, etc. 
It contains no useless theory; everything is to the point. It teaches you just what you want 
to know about electricity. It is the standard work published on the subject. Forty-one 
chapters, 610 engravings, handsomely bound in red leather with title and edges in gold. Price: 

$3.50 

ELECTRICITY IN FACTORIES AND WORKSHOPS, ITS COST AND CONVENIENCE. 

By Arthur P. Haslam. 

A practical book for power producers and power users showing what a convenience the electric 
motor, in its various forms, has become to the modern manufacturer. It also deals with the 
conditions which determine the cost of electric driving, and compares this with other methods 
of producing and utilizing power. 

Among the chapters contained in the book are: The Direct Current Motor; The Alternating 
Current Motor; The Starting and Speed Regulation of Electric Motors; The Rating and 
Efficiency of Electric Motors; The Cost of Energy as Affected by Conditions of Working, The 
Question for the Small Power User; Independent Generating Plants; Oil and Gas Engine 
Plants; Steam Plants; Power Station Tariffs; The Use of Electric Power in Textile Factories; 
Electric Power in Printing Works; The Use of Electric Power in Engineering Workshops 
Miscellaneous Application of Electric Power; The Installation of Electric Motors; The Lighting 
of Industrial Establishments. 312 pages. Very fully illustrated. Price .... $2.50 

ELECTRICITY SIMPLIFIED. By Prof. T. O’Conor Sloane. 

The object of “Electricity Simplified” is to make the subject as plain as possible and to show 
what the modern conception of electricity is; to show how two plates of different metals 
immersed in acid can send a message around the globe; to explain how a bundle of copper wire 
rotated by a steam engine can be the agent in lighting our streets, to tell what the volt, ohm 
and ampere are, and what high and low tension mean; and to answer the questions that 
perpetually arise in the mind in this age of electricity. 172 pages. Illustrated. Price $ 1 00 


IO 





CATALOGUE OF GOOD, PRACTICAL BOOKS 


HOUSE WIRING. By Thomas W. Poppe. 

This work describes and illustrates the actual installation of Electric Light Wirin" the manner 

oa-ded^ in th^°‘Socket It" t°Tn f ™'l t l K V’ U ' t , 1 ! 0d ^The b™kcanKS“ 
carried in tne pocket, it is intended for the Electrician, Helper and Apprentice it 

U s ^ roblems, and contains nothing that conflicts with the rulings of the Nation- 

? v . oard of 1 ire Lnderwriters. It gives just the information essential to the Successful 

irmg of a Building. Among the subjects treated are: Locating the Meter. Panel Boards 

r W1 in”' 1 kig Keceptacles. Brackets. Ceiling Fixtures. The Meter Connections The 

Teed M ires. The Steel Armored Cable System. The Flexible Steel Conduit t)ip 

Kidig Conduit System A digest of the National Board of Fire Undenvriters’ ‘mk^ relatin- 

The^easiest method^Ss}in^ fhPml switch * n S arrangements explained and diagrammed” 
if aif a ^o?oiu!f th ° • of tes T n S the Three and Four-way circuits explained. The grounding 
of all metallic wiring systems and the reason for doing so shown and explained The in¬ 
sulation of the metal parts of lamp fixtures and the reason for the same described and 
illustrated. 12o pages. Fully illustrated. Flexible cloth. Price. ... 50 cents 


HOW TO BECOME A SUCCESSFUL ELECTRICIAN. By Prof. T. O’Conor Sloane. 

Every young man who wishes to become a successful electrician should read this book. It tells 
m simple language the surest and easiest way to become a successful electrician. The studies 
to be followed, methods of work, field of operation and the requirements of the successful 
electrician are pointed out and fully explained. Every young engineer will find this an ex¬ 
cellent stepping-stone to more advanced works on electricity which he must master before 
success can be attained. Many young men become discouraged at the very outstart by 
attempting to read and study books that are far beyond their comprehension. This book 
serves as the connecting link between the rudiments taught in the public schools and the real 
study of electricity. It is interesting from cover to cover. Fifteenth edition. 202 pages 
Illustrated. Price .$1,00 


MANAGEMENT OF DYNAMOS. By Lummis-Paterson. 

A handbook of theory and practice. This work is arranged in three parts. The first part 
covers the elementary theory of the dynamo. The second part, the construction and action 
of the different classes of dynamos in common use are described; while the third part relates 
to such matters as affect the practical management and working of dynamos and motors 
The following chapters are contained in the book: Electrical Units; Magnetic Principles- 
Theory of the Dynamo; Armature; Armature in Practice; Field Magnets; Field Magnets in 
Practice; Regulating Dynamos; Coupling Dynamos; Installation, Running, and Maintenance 
of Dynamos; Faults in Dynamos; Faults in Armatures; Motors. 292 pages. 117 illustra¬ 
tions. Price.$1.50 


STANDARD ELECTRICAL DICTIONARY. By T. O’Conor Sloane. 

An indispensable work to all interested in electrical science. Suitable alike for the student 
and professional. A practical hand-book of reference containing definitions of about 5,000 
distinct words, terms and phrases. The definitions are terse and concise and include every 
term used in electrical science. Recently issued. An entirely new edition. Should be in the 
possession of all who desire to keep abreast with the progesss of this branch of science. In 
its arrangement and typography the book is very convenient. The word or term defined is 
printed in black-faced type which readily catches the eye, while the body of the page is in 
smaller but distinct type. The definitions are well worded, and so as to be understood by 
the non-technical reader. The general plan seems to be to give an exact, concise definition, 
and then amplify and explain in a more popular way. Synonyms are also given, and refer¬ 
ences to other words and phrases are made. A very complete and accurate index of fifty 
pages is at the end of the volume; and as this index contains all synonyms, and as all phrases 
are indexed in every reasonable combination of words, reference to the proper place in the 
body of the book is readily made. It is difficult to decide how far a book of this character 
is to keep the dictionary form, and to what extent it may assume the encyclopedia form. 
For some purposes, concise, exactly worded definitions are needed; for other purposes, more 
extended descriptions are required. This book seeks to satisfy both demands, and does it 
with considerable success. Complete, concise, and convenient. 682 pages. 393 illustra¬ 
tions. Twelfth edition. Price.$3.00 


SWITCHBOARDS. By William Baxter, Jr. 

This book appeals to every engineer and electrician who wants to know the practical side of 
things. It takes up all sorts and conditions of dynamos, connections and circuits and shows 
by diagram and illustration just how the switchboard should be connected. Includes direct 
and alternating current boards, also those for arc lighting, incandescent, and power circuits. 
Special treatment on high voltage boards for power transmission. 2d Edition. 190 pages. 
Illustrated. Price... $1.50 


II 









CATALOGUE OF GOOD, PRACTICAL BOOKS 


TELEPHONE CONSTRUCTION, INSTALLATION, WIRING, OPERATION AND 
MAINTENANCE. By W. H. Radcliffe and H. C. Cushing. 

This book gives the principles of construction gnd operation of both the Bell and Independent 
instruments; approved methods of installing and wiring them; the means of protecting them 
from lightning and abnormal currents; their connection together for operation as series or 
bridging stations; and rules for their inspection and maintenance. Line wiring and the wir¬ 
ing and operation of special telephone systems are also treated. 

Intricate mathematics are avoided, and all apparatus, circuits and systems are thoroughly 
described. The appendix contains definitions of units and terms used in the text. Selected 
wiring tables, which are very helpful, are also included. Among the subjects treated are 
Construction. Operation, and installation of Telephone Instruments, Inspection and Main¬ 
tenance of Telephone Instruments; Telephone Line Wiring; Testing Telephone Line Wires 
and Cables; Wiring and Operation of Special Telephone Systems, etc. 100 pages, 125 illus¬ 
trations.$1.00 

WIRELESS TELEGRAPHY AND TELEPHONY SIMPLY EXPLAINED. 

By Alfred P. Morgan. 

This is undoubtedly one of the most complete and comprehensible treatises on the subject 
ever published, and a close study of its pages will enable one to master all the details of the 
wireless transmission of messages. The author has filled a long felt want and has succeeded 
in furnishing a lucid, comprehensible explanation in simple language of the theory and 
practice of wireless telegraphy and telephony. 

Among the contents are: Introductory; Wireless Transmission and Reception—The 
Aerial System, Earth Connections—The Transmitting Apparatus, Spark Coils and Trans¬ 
formers, Condensers, Helixes, Spark Gaps, Anchor Gaps, Aerial Switches—The Receiving 
Apparatus, Detectors, etc.—Tuning and Coupling, Tuning Coils, Loose Couplers, Variable 
Condensers, Directive Wave Systems—Miscellaneous Apparatus, Telephone Receivers, 
Range of Stations, Static, Interference—Wireless Telephones,. Sound and Sound Waves, The 
Vocal Cords and Ear—Wireless Telephones, How Sounds are changed into Electric Waves— 
Wireless Telephones, The Apparatus—Summary. 200 pages. 150 engravings. Price $1.00 

WIRELESS TELEPHONES AND HOW THEY WORK. By James Erskine-Murray. 

This work is free from elaborate details and aims at giving a clear survey of the way in which 
Wireless Telephones work. It is intended for amateur workers and for those whose knowledge 
of electricity is slight. Chapters contained: How We Hear; Historical; The Conversion of 
Sound into Electric Waves; Wireless Transmission; The Production of Alternating Currents 
of High Frequency; How the Electric Waves are Radiated and Received; The Receiving 
Instruments; Detectors; Achievements and Expectations; Glossary of Technical Words 
Cloth. Price.. $1.00 

WIRING A HOUSE. By Herbert Pratt. 

Shows a house already built; tells just how to start about wiring it; where to begin; what 
wire to use; how to run it according to Insurance Rules; in fact just the information you need. 
Directions apply equally to a shop. Fourth edition. 25 cents 


FACTORY MANAGEMENT, ETC. 


MODERN MACHINE SHOP CONSTRUCTION, EQUIPMENT AND MANAGEMENT. 

By O. E. Perrigo, M.E. 

The only work published that describes the modern machine shop or manufacturing plant from 
the time the grass is growing on the site intended for it until the finished product is shipped 
By a careful study of its thirty-two chapters the practical man may economically build* 
efficiently equip, and successfully manage the modern machine shop or manufacturing estab- 
ishment. Just the book needed by those contemplating the erection of modern shop buildings 
the re-building and re-organization of old ones, or the introduction of modern shop methods’ 
time and cost system. It is a book written and illustrated by a practical shop man for practical 
shop men who are too busy to read theories and want facts. It is the most complete all around 
book of its kind ever published. It is a practical book for practical men, from the apprentice 
in the shop to the president in the office. It minutely describes and illustrates the most simple 
and yet the most efficient time and cost system yet devised. Price. $5 00 


12 










CATALOGUE OF GOOD, PRACTICAL BOOKS 


FUEL 


COMBUSTION OF COAL AND THE PREVENTION OF SMOKE. By Wm. M. Barr. 

This book has been prepared with special reference to the generation of heat by the combus¬ 
tion of the common fuels found in the United States, and deals particularly with the condi¬ 
tions necessary to the economic and smokeless combustion of bituminous coals in Stationary 
and Locomotive Steam Boilers. 

The presentation of this important subject is systematic.and progressive. The arrangement 
of the book is in a series of practical questions to which are appended accurate answers, 
which describe in language, free from technicalities, the several processes involved in the 
furnace combustion of American fuels; it clearly states the essential requisites for perfect 
combustion, and points out the best methods for furnace construction for obtaining the great¬ 
est quantity of heat from any given quality of coal. Nearly 350 pages, fully illustrated. 
Price.'J.$1.00 

SMOKE PREVENTION AND FUEL ECONOMY. By Booth and Kershaw. 

A complete treatise for all interested in smoke prevention and combustion, being based on 
the German work of Ernst Schmatolla, but it is more than a mere translation of the German 
treatise, much being added. The authors show as briefly as possible the principles of fuel 
combustion, the methods which have been and are at present in use, as well as the proper 
scientific methods for obtaining all the energy in the coal and burning it without smoke. 
Considerable space is also given to the examination of the waste gases, and several of the 
representative English and American mechanical stoker and similar appliances are described. 
The losses carried away in the waste gases are thoroughly analyzed and discussed in the Ap- 

E endix, and abstracts are also here given of various patents on combustion apparatus. The 
ook is complete and contains much of value to all who have charge of large plants. 194 
pages. Illustrated. Price.$2.50 


GAS ENGINES AND GAS 


GASOLINE ENGINES : THEIR OPERATION, USE AND CARE. By A. Hyatt 
Verrill. ' 

The Simplest, Latest and Most Comprehensive popular work published on Gasoline Engines 
describing what the Gasoline engine is; its construction and operation; how to install it; 
how to select it; how to use it and how to remedy troubles encountered. Intended for owners, 
Operators and Users of Gasoline Motors of all kinds. This work fully describes and illus¬ 
trates the various types of Gasoline engines used in Motor Boats, Motor Vehicles and 
Stationary Work. The parts, accessories and Appliances are described, with chapters on 
ignition, fuel, lubrication, operation and engine troubles. Special attention is given to the 
care, operation and repair of motors with useful hints and suggestions on emergency re¬ 
pairs and make-shifts. A complete glossary of technical terms and an alphabetically ar¬ 
ranged table of troubles and their symptoms form most valuable and unique features of this 
manual. Nearly every illustration in the book is original, having been made by the author. 
Every page is full of interest and value. A book which you cannot afford to be without. 320 
pages. NeaGy 150 specially made engravings. Price.$1.50 


GAS, GASOLINE, AND OIL ENGINES. By Gardner D. Hiscox. 

Just issued, 20th revised and enlarged edition. Every user of a gas engine needs this book. 
Simple, instructive, and right up-to-date. The only complete work on the subject. Tells 
all about the running and management of gas, gasoline and oil engines, as designed and manu¬ 
factured in the United States. Explosive motors for stationary marine and vehicle power are 
fully treated, together with illustrations of their parts and tabulated sizes, also their care and 
running are included. Electric ignition by induction coil and jump spark are fully explained 
and illustrated, including valuable information on the testing for economy and power and the 
erection of power plants. 

The rules and regulations of the Board of Fire Underwriters in regard to the installation an 1 
management of gasoline motors is given in full, suggesting the safe installation of explosive 
motor power. A list of United States Patents issued on gas, gasoline, and oil engines and their 
adjuncts from 1875 to date is included. 484 pages. 410 engravings Price . . . $2.50 

MODERN GAS ENGINES AND PRODUCER GAS PLANTS. By R. E. Mathot, M.E. 

a e-nide for the eas engine designer, user, and engineer in the construction, selection, purchase 
installation operltion and maintenance of gas engines. More than one book on gas engines 
has been written but not one has thus far even encroached on the field covered by this > book. 
Above all Mr. Mathot’s work is a practical guide. Recognizing the need of a volume that 


13 












CATALOGUE OF GOOD, PRACTICAL BOOKS 


would assist the gas engine user in understanding thoroughly the motor upon which he depends 
for power, the author has discussed his subject without the help of any mathematics and 
without elaborate theoretical explanations. Every part of the gas engine is described in detail, 
tersely, clearly, with a thorough understanding of the requirements of the mechanic. Helpful 
suggestions as to the purchase of an engine, its installation, care, and operation form a most 
\ aluable feature of the work. 320 pages. 175 detailed illustrations. Price . . . $2.50 

GAS ENGINE CONSTRUCTION, OR HOW TO BUILD A HALF-HORSE-POWER 

GAS ENGINE’ By Parsell and Weed. 

A practical treatise of 300 pages describing the theory and principles of the action of Gas 
Engines of various types and the design and construction of a half-horse power Gas Engine, with 
illustrations of the work in actual progress, together with the dimensioned working drawings 
giving clearly the sizes of the various details; for the student, the scientific investigator and the 
amateur mechanic. 

Tnis book treats of the subject more from the standpoint of practice than that of theory. The 
principles of operation of Gas Engines are clearly and simply described and then the actual 
construction of a half-horse power engine is taken up, step by step, showing in detail the making 
of the Gas Engine. 3d Edition. 300 pages. Price.$2.50 

THE GASOLINE ENGINE ON THE FARM: ITS OPERATION, REPAIR 

AND USES. By Xeno W. Putnam. 

This is a practical treatise on the Gasoline and Kerosene engine intended for the man who 
wants to know just how to manage his engine and how to apply it to all kinds of farm work 
to the best advantage. 

The book includes selecting the most suitable engine for farm work, its most convenient and 
efficient installation, with chapters on troubles, their remedies and how to avoid them. 
The care and management of the farm tractor in plowing, harrowing, harvesting and road 
grading are fully covered; also plain directions are given for handling the tractor on the road. 
Special attention is given to relieving farm life of its drudgery by applying power to the 
disagreeable small tasks which must otherwise be done by hand. Many homemade con¬ 
trivances for cutting wood, supplying kitchen, garden and barn with water, loading, hauling 
and unloading hay, delivering grain to the bins or the feed trough are included; also full 
directions for making the engine milk the cows, churn, wash, sweep the house and clean the 
windows, etc. Very fully illustrated with drawings of working parts and cuts showing 
Stationary. Portable and Tractor Engines doing all kinds of farm work. 300 pages. Nearly 
150 engravings. 12mo. Price. .$1.50 

CHEMISTRY OF GAS MANUFACTURE. By H. M. Royles. 

This book covers points likely to arise in the ordinary course of the duties of the engineer or 
manager of a gas works not large enough to necessitate the employment of a separate chemical 
staff. It treats of the testing of the raw materials employed in the manufacture of illuminat¬ 
ing coal gas, and of the gas produced. The preparation of standard solutions is given as well 
as the chemical and physical examination of gas coal including among its contents—Prepa- 
ratipns of Standard Solutions, Coal, Furnaces, Testing and Regulation. Products of Car¬ 
bonization. Analysis of Crude Coal Gas. Analysis of Lime. Ammonia. Analysis of Oxide 
of Iron. Naphthalene. Analysis of Fire-Bricks and Fire-Clay. Weldom and Spent Oxide. 
Photometry and Gas Testing. Carburetted Water Gas. Metropolis Gas. Miscellaneous 
Extracts. Lseful Tables. $4.50 

GEARING AND CAMS 


BEVEL GEAR TABLES. By D. Ag. Engstrom. 

A book that will at once commend itself to mechanics and draftsmen. Does away with all 
the trigonometry and fancy figuring on bevel gears and makes it easy for anyone to lay them 
out or make them just right. There are 36 full-page tables that show every necessary dimen¬ 
sion for all sizes or combinations you’re apt to need. No puzzling figuring or guessing 
Gives placing distance, all the angles (including cutting angles), and the correct cutter to use’ 
A copy of this prepares you for anything in the bevel gear line. 66 pages. . $1.00 

CHANGE GEAR DEVICES. By Oscar E. Perrigo. 

A practical book for every designer, draftsman, and mechanic interested in the invention and 
development of the devices for feed changes on the different machines requiring such mechan¬ 
ism. All the necessary information on this subject is taken up, analyzed, classified, sifted 
and concentrated for the use of busy men who have not the time to go through the masses 
of irrelevant matter with which such a subject is usually encumbered and select such infor¬ 
mation as will be useful to them. 

It shows just what has been done, how it has been done, when it was done, and who did it. 
It saves time in hunting up patent records and re-inventing old ideas. 88 pages. $1.00 


14 










CATALOGUE OF GOOD, PRACTICAL BOOKS 


DRAFTING OF CAMS. By Louis Rouillion. 

The laying out of cams is a serious problem unless you know how to go at it right. This puts 
you on the right road for practically any kind of cam you are likely to run up against. 25 cents 

HYDRAULICS 


HYDRAULIC ENGINEERING. By Gardner D. Hiscox. 

A treatise on the properties, power, and resources of water for all purposes. Including the 
measurement of streams, the flow of water in pipes or conduits; the horse-power of falling 
water; turbine and impact water-wheels, wave motors, centrifugal, reciprocating, and air¬ 
lift pumps. With 300 figures and diagrams and 36 practical tables. 

All who are interested in water-works development will find this book a useful one, because 
it is an entirely practical treatise upon a subject of present importance, and cannot fail in 
having a far-reaching influence, and for this reason should have a place in the working library 
of every engineer. Among the subjects treated are: Historical—Hydraulics, Properties of 
Water; Measurement of the flow of Streams; Flow from Subsurface orifices and nozzles; 
Flow of water in Pipes; Siphons of various kinds; Dams and Great Storage Reservoirs; 
City and Town Water Supply; AYells and their reenforcement; Air lift methods of raising 
water; artesian wells; Irrigation of Arid districts; Water Power, Water Wheels; Pumps and 
Pumping Machinery; Reciprocating Pumps; Hydraulic Power Transmission; Hydraulic 
Mining; Canals; Ditches; Conduits and Pipe Lines; Marine Hydraulics; Tidal and Sea 
Wave power, etc. 320 pages. Price.*.$4.00 


ICE AND REFRIGERATION 


POCKET BOOK OF REFRIGERATION AND ICE MAKING. By A. J. Wallis- 
Taylor. 

This is one of the latest and most comprehensive reference books published on the subject of 
refrigeration and cold storage. It explains the properties and refrigerating effect of the different 
fluids in use, the management of refrigerating machinery and the construction and insulation 
of cold rooms with their required pipe surface for different degrees of cold; freezing mixtures 
and non-freezing brines, temperatures of cold rooms for all kinds of provisions, cold storage 
charges for all classes of goods, ice making and storage of ice, data and memoranda for constant 
reference by refrigerating engineers, with nearly one hundred tables containing valuable 
references to every fact and condition required in the installment and operation of a refrigerat¬ 
ing plant. Illustrated. (5th Edition, revised.) Price.$1.50 


INVENTIONS—PATENTS 

INVENTOR’S MANUAL, HOW TO MAKE A PATENT PAY. 

This is a book designed as a guide to inventors in perfecting their inventions, taking out their 
oatents and disposing of them. It is not in any sense a Patent Solicitor s Circular, nor a 
Patent Broker’s Advertisement. No advertisements of any description appear in the work. 
It is a book containing a quarter of a century’s experience of a successful inventor, together 
with notes based upon the experience of many other inventors. 

Among the subjects treated in this work are: How to Invent. How to Secure a Good 
Patent. Value of Good Invention. How to exhibit an Invention. How to Interest 
CaDital. How to Estimate the Value of a Patent. Value of Design Patents. A alue of 
Foreign Patents. Value of Small Inventions. Advice on Selling Patents. Adduce on the 
Formation of Stock Companies. Advice on the Formation of Limited Lj& bl .hty 
Advice on Disposing of Old Patents. Advice as to Patent Attorneys. Advice as to Selling 
Agents Forms of Assignments. License and Contracts. State Laws Concerning Patent 
R?ghts. 1900 Census of the United States by counties of over 10,000 population. Revised 
edition. 120 pages. Price.. 


KNOTS 


KNOTS, SPLICES AND ROPE WORK. By A. Hyatt Verrill. 

This is a nractical book giving complete and simple directions for making all the most use- 
M and ornimentol knots in commoii use. with chapters on Splicing, Pointing. Seizing, 















CATALOGUE OF GOOD, PRACTICAL BOOKS 


Serving, etc. This book is fully illustrated with one hundred and fifty original engravings, 
which show how each knot, tie or splice is formed and its appearance when finished. The 
book will be found of the greatest value to Campers, Yachtsmen, Travelers, Boy Scouts, 
in fact to anyone having occasion to use or handle rope or knots for any purpose. The book 
is thoroughly reliable and practical and is not only a guide but a teacher. It is the standard 
work on the subject. Among the contents are: 1. Cordage, Kinds of Rope. Construction 
of Rope, Parts of Rope Cable and Bolt Rope. Strength of Rope, Weight of Rope. 2. Sim¬ 
ple knots and Bends. Terms used in Handling Rope. Seizing Rope. 3. Ties and Hitches. 
4. Noose, Loops and Mooring Knots. 5. Shortenings, Grommets and Selvages. 6. Lash¬ 
ings. Seizings and Splices. 7. Fancy Knots and Rope Work. 128 pages. 150 original 
engravings. Price.60 cents 


LATHE WORK 


MODERN AMERICAN LATHE PRACTICE. By Oscar E. Perrigo. 

This is a new book from cover to cover, and the only complete American work on the subject 
written by a man who knows not only how work ought to be done, but who also knows 
how to do it, and how to convey this knowledge to others. It is strictly up-to-date in its 
descriptions and illustrations, which represent the very latest practice in lathe and boring 
mill operations as well as the construction of and latest developments in the manufacture 
of these important classes of machine tools. 

Lathe history and the relations of the Lathe to manufacturing are given; also a description 
of the various devices for Feeds and Thread Cutting mechanisms from early efforts in this 
direction to the present time. Lathe design is thoroughly discussed, including Back Gearing, 
Driving Cones, Thread Cutting Gears, and all the essential elements of the modern Lathe. 
The classification of Lathes is taken up, giving the essential differences of the several types 
of Lathes, including, as is usually understood, Engine Lathes, Bench Lathes, Speed Lathes, 
Forge Lathes, Gap Lathes, Pulley Lathes, Forming Lathes, Multiple Spindle Lathes, Rapid 
Reduction Lathes, Precision Lathes, Turret Lathes, Special Lathes, Electrically Driven 
Lathes, etc. 424 pages. 314 illustrations. Price. ....... $2.60 

PRACTICAL METAL TURNING. By Joseph G. Horner. 

This important and practical subject is treated in a full and exhaustive manner and nothing 
of importance is omitted. The principles and practice and all tbe different branches of Turn¬ 
ing are considered and well illustrated. All the different kinds of Chucks of usual forms, as 
well as some unusual kinds, are shown. A feature of the book is the important section de¬ 
voted to modern Turret practice; Boring is another subject which is treated fully; and the 
chapter on Tool Holders illustrates a large number of representative types. Thread Cutting 
is treated at reasonable length; and the last chapter contains a good deal of information 
relating to the High-Speed Steels and their work. The numerous tools used by machinists 
are illustrated, and also the adjuncts of the lathe. In fact, the entire subject is treated in 
such a thorough manner as to make this book the standard one on the subject. It is indis¬ 
pensable to the manager, engineer, and machinist as well as to the student, amateur, and 
experimental man who desires to keep up-to-date. 400 pages, fully illustrated. Price $3.50 

TURNING AND BORING TAPERS. By Fred H. Colvin. 

There are two ways to turn tapers; the right way and one other. This treatise has to do with 
the right way; it tells you how to start the work properly, how to set the lathe, what tools to 
use and how to use them, and forty and one other little things that you should know. Fourth 
edition. 25 cents 


LIQUID AIR 


LIQUID AIR AND THE LIQUEFACTION OF GASES. By T. O’Conor Sloane. 

This book gives the history of the theory, discovery, and manufacture of Liquid Air, and 
contains an illustrated description of all the experiments that have excited the wonder of 
audiences all over the country. It shows how liquid air, like water, is carried hundreds of 
miles and is handled in open buckets. It tells what may be expected from it in the near 
future. 

A book that renders simple one of the most perplexing chemical problems of the century. 
Startling developments illustrated by actual experiments. 

It is not only a work of scientific interest and authority, but is intended for the general reader, 
oeing written in a popular style—easily understood by every one. Second edition. 365 
pages. Price . $2.00 


16 














CATALOGUE OF GOOD, PRACTICAL BOOKS 


LOCOMOTIVE ENGINEERING 


AIR-BRAKE CATECHISM. By Robert H. Blackall. 



350 pages, fully illustrated with folding plates and dia- 
.. 


grams. 


AMERICAN COMPOUND LOCOMOTIVES. By Fred. H. Colvin. 



Cylinder Compound. Rhode Island Compound. Richmond Compound. Rogers Compound 
Schenectady Two-Cylinder Compound. Vauclain Compound. Tandem Compounds Bald¬ 
win Tandem. The Colvin-Wight man Tandem. Schenectady Tandem. Balanced Loco¬ 
motives. Baldwin Balanced Compound. Plans for Balancing. Locating Blows Break¬ 
downs. Reducing Valves. Drifting. Valve Motion. Disconnecting. Power of Compound 
Locomotives. Practical Notes. 

Fully illustrated [and containing ten special “Duotone” inserts on heavy Plate Paper show¬ 
ing different types of Compounds. 142 pages. Price.’$1.00 

APPLICATION OF HIGHLY SUPERHEATED STEAM TO LOCOMOTIVES. By 

Robert Garbe. 

A practical book. Contains special chapters on Generation of Highly Superheated Steam; 
Superheated Steam and the Two-Cylinder Simple Engine; Compounding and Superheating; 
Designs ofj Locomotive Superheaters; Constructive Details of Locomotives using Highly 
Superheated Steam; Experimental and Working Results. Illustrated with folding plates 


and tables. Price 


$2.50 


COMBUSTION OF COAL AND THE PREVENTION OF SMOKE. 
By Wm. M. Barr. 


This book has been prepared with special reference to the generation of heat by the combus¬ 
tion of the common fuels found in the United States, and deals particularly with the condi¬ 
tions necessary to the economic and smokeless combustion of bituminous coal in Stationary 
and Locomotive Steam Boilers. 

The presentation of this important subject is systematic and progressive. The arrangement 
of the book is in a series of practical questions to which are appended accurate answers, 
which describe in language, free from technicalities, the several processes involved in the 
furnace combustion of American fuels; it clearly states the essential requisites for perfect 
combustion, and points out the best methods of furnace construction for obtaining the 
greatest quantity of heat from any given quality of coal. Nearly 350 pages, fully illustrated. 
Price.$1.00 

DIARY OF A ROUND HOUSE FOREMAN. By T. S. Reilly . 

This is the greatest book of railroad experiences ever published. Containing a fund of infor¬ 
mation and suggestions along the line of handling men, organizing, etc., that one cannot afford 
to miss. 176 pages. Price.$1.00 

LINK MOTIONS, VALVES AND VALVE SETTING. By Fred H. Colvin, Associate 
Editor of “ American Machinist.” 

A handy book for the engineer or machinist that clears up the mysteries of valve setting. 
Shows the different valve gears in use, how they work, and why. Piston and slide valves 
of different types are illustrated and explained. A book that every railroad man in the mo¬ 
tive power department ought to have. Contains chapters on Locomotive Link Motion, 
Valve Movements, Setting Slide Valves, Analysis by Diagrams, Modern Practice, Slip of 
Block Slide Valves, Piston Valves, Setting Piston Valves, Joy-Alien Valve Gear, Walschaert 
Valve’ Gear, Gooch Valve Gear, Alfree-Hubbell Valve Gear, etc., etc. Fully illustrated. 


Price 


50 cents 


i7 

















CATALOGUE OF GOOD, PRACTICAL BOOKS 


LOCOMOTIVE BOILER CONSTRUCTION. By Frank A. Kleinhans. 

The construction of boilers in general is treated, and following this, the locomotive boiler 
is taken up in the order in which its various parts go through the simp, chows all types of 
boilers used; gives details of construction; practical facts, such as life of riveting, punches 
and dies; work done per day, allowance for bending and flanging sheets, and other data. 
Locomotive boilers present more difficulty in laying out and building than any other type, 
and for this reason the author uses them as examples. Anyone who can handle them can 
tackle anything. 

Contains chapters on Laying Out Work; Flanging and Forging; Punching; Shearing; Plate 
Planing; General Tables; Finishing Parts; Bending; Machinery Parts; Riveting; Boiler 
Details; Smoke Box Details; Assembling and Calking; Boiler Shop Machinery, etc., etc. 
There isn’t a man who has anything to do with boiler work, either new or repair work, who 
doesn’t need this book. The manufacturer, superintendent, foreman, and boiler worker— 
all need it. No matter what the type of boiler, you’ll find a mint of information that you 
wouldn’t be without. Over 400 pages, five large folding plates. Price.$o.00 

LOCOMOTIVE BREAKDOWNS AND THEIR REMEDIES. By Geo. L. Fowler. 

Revised by Wm. W. Wood, Air-Brake Instructor. Just issued. Revised pocket 
edition. 

It is out of the question to try and tell you about every subject that is covered in this pocket 
edition of Locomotive Breakdowns. Just imagine all the common troubles that an engineer 
may expect to happen some time, and then add all of the unexpected ones, troubles that could 
occur, but that you had never thought about, and you will find that they are all treated with 
the very best methods of repair. Walschaert Locomotive Valve Gear Troubles, Electric 
Headlight Troubles, as well as Questions and Answers on the Air Brake are all included. 294 
pages. 7th Revised Edition. Fully illustrated. $1.00 

LOCOMOTIVE CATECHISM. By Robert Grimshaw. 

The revised edition of “Locomotive Catechism,” by Robert Grimshaw, is a New Book from 
Cover to Cover. It contains twice as many pages and double the number of illustrations 
of previous editions. Includes the greatest amount of practical information ever published 
on the construction and management of modern locomotives. Specially Prepared Chapters 
on the Walschaert Locomotive Valve Gear, the Air Brake Equipment and the Electric Head 
Light are given. 

It commends itself at once to every Engineer and Fireman, and to all who are going in for 
examination or promotion. In plain language, with full complete answers, not only all the 
questions asked by the examining engineer are given, but those which the young and less 
experienced would ask the veteran, and which old hands ask as “stickers.” It is a veritable 
Encyclopedia of the Locomotive, is entirely free from mathematics, easily understood and 
thoroughly up-to-date. Contains over 4,000 Examination Questions with their Answers. 
825 pages, 437 illustrations and three folding plates. 28th Revised Edition. . . $2.50 

PRACTICAL INSTRUCTOR AND REFERENCE BOOK FOR LOCOMOTIVE 
FIREMEN AND ENGINEERS. By Chas. F. Lockhart. 

An entirely new book on the Locomotive. It appeals to every railroad man, as it tells him 
how things are done and the right way to do them. Written by a man who has had years 
of practical experience in locomotive shops and on the road firing and running. The infor¬ 
mation given in this book cannot be found in any other similar treatise. Eight hundred and 
fifty-one questions with their answers are included, which will prove specially helpful to 
those preparing for examination. Practical information on: The Construction"and Opera¬ 
tion of Locomotives. Breakdowns and their Remedies; Air Brakes and Valve Gears. 
Rules and Signals are handled in a thorough manner. As a book of reference it cannot be 
excelled. The book is divided into six parts, as follows: 1. The Fireman’s Duties. 2. 
General description of the Locomotive. 3. Breakdowns and their Remedies. 4. Air Brakes. 
5. Extracts from Standard Rules. 6. Questions for examination. The 851 questions have 
been carefully selected and arranged. These cover the examinations required by the different 
railroads. 368 pages. 88 illustrations. Price. $1.50 

PREVENTION OF RAILROAD ACCIDENTS, OR SAFETY IN RAILROADING. 

By George Bradshaw. 

This book is a heart-to-heart talk with Railroad Employees, dealing with facts, not theories, 
and showing the men in the ranks, from every-day experience, how accidents occur and how 
they may be avoided. The book is illustrated with seventy original photographs and draw¬ 
ings showing the safe and unsafe methods of work. No visionary schemes, no ideal pictures. 
Just plain facts and Practical Suggestions are given. Every railroad employee who reads the 










CATALOGUE OF GOOD, PRACTICAL BOOKS 


book is a better and. safer man to liave in railroad service. It gives just the information 
which will be the means of preventing many injuries and deaths. All railroad employees 
should procure a copy, read it, and do your part in preventing accidents. 169 pages. Pocket 
Size. Fully illustrated. Price.50 cents 

TRAIN RULE EXAMINATIONS MADE EASY. By G. E. Collingwood. 

This is the only practical work on train-rules in print. Every detail is covered, and puzzling 
points are explained in simple, comprehensive language, making it a practical treatise for 
the Train Dispatcher, Engineman, Trainman, and all others who na Tr e to do with the move¬ 
ments of trains. Contains complete and reliable information of the Standard Code of Train 
Rules for single track. Shows Signals in Colors, as used on the different roads. Explains 
fully the practical application of train orders, giving a clear and definite understanding of all 
orders which may be used. The meaning and necessity for certain rules are explained in 
such a manner that the student may know beyond a doubt the rights conferred under any 
orders he may receive or the action required by certain rules. 

As nearly all roads require trainmen to pass regular examinations, a complete set of examina¬ 
tion questions, with their answers, are included. These will enable the student to pass the 
required examinations with credit to himself and the road for which he works. 256 pages,. 
Fully illustrated with Train Signals in colors. Price.$1.25 

TRAIN RULES AND DESPATCHING. By H. A. Dalby. 

Every railroad man, no matter what department he’s in, needs a copy of this book. It gives 
the standard rules for both single and double track, shows all the signals, with colors wher¬ 
ever necessary, and has a list of towns where time changes, with a map showing the whole 
country. The rules are explained wherever there is any doubt about their meaning or where 
they are modified by different railroads. It’s the only practical book on train rules in print. 
Over 220 pages. Leather cover. Price.$1.50 


THE WALSCHAERT AND OTHER MODERN RADIAL VALVE GEARS FOR 
LOCOMOTIVES. By Wm. W. Wood. 

If you would thoroughly understand the Walschaert Valve Gear you should possess a copy 
of this book, as the author takes the plainest form of a steam engine—a stationary engine in 
the rough, that will only turn its crank in one direction—and from it builds up—with the 
reader’s help—a modern locomotive equipped with the Walschaert Valve Gear, complete. 
The points discussed are clearly illustrated: two large folding plates that show the positions 
of the valves of both inside or outside admission type, as well as the links and other parts of 
the gear w'hen the crank is at nine different points in its revolution, are especially valuable 
in making the movement clear. These employ sliding cardboard models which are contained 
in a pocket in the cover. 

The book is divided into five general divisions, as follows: I. Analysis of the gear. II. De¬ 
signing and erecting the gear. III. Advantages of the gear. IV. Questions and answers 
relating to the Walschaert Valve Gear. V. Setting valves with the Walschaert Valve Gear; 
the three primary types of locomotive valve motion; modern radial valve gears other than 
the Walschaert: the Hobart All-free valve and valve gear, with questions and answers on 
breakdowns; the Baker-Pilliod valve gear; the Improved Baker-Pilliod Valve Gear, with 
questions and answers on breakdowns. 

The questions with full answers given will be especially valuable to firemen and engineers 
in preparing for an examination for promotion. 245 pages. Third Revised Edition. 
Price.. 


WESTINGHOUSE E—T AIR-BRAKE INSTRUCTION POCKET BOOK. By Wm. 

W. Wood, Air-Brake Instructor. 

Here is a book for the railroad man, and the man who aims to be one. It is without doubt 
the only complete work published on the Westinghouse E-T Locomotive Brake Equipment. 
Written by an Air Brake Instructor who knows just what is needed. It covers the subject 
thoroughly Everything about the New' Westinghouse Engine and Tender Brake Equip¬ 
ment including the Standard No. 5 and the Perfected No. 6 Style of brake, is treated in de¬ 
tail Written in plain English and profusely illustrated with Colored Plates, w'hich enable 
one’ to trace the flow of pressures throughout the entire equipment. The best book ever 
published on the Air Brake. Equally good for the beginner and the advanced engineer. 
Will pass any one through any examination. It informs and enlightens you on every point. 
Indispensable to every engineman and trainman. 

Contains examination questions and answers on the E-T equipment. Covering what the 
E-T Brake is. How it should be operated. What to do when defective. Not a question can 
be asked of the engineman up for promotion on either the No. 5 or the ISo. 6 E- I equipment 
that is not asked and answered in the book. If you want to thoroughly understand the E-T 
equipment get a copy of this book. It covers every detail. Makes Air Brake troubles and 
examinations easy. Price.. 


x 9 













CATALOGUE OF GOOD, PRACTICAL BOOKS 


MACHINE SHOP PRACTICE 


AMERICAN TOOL MAKING AND INTERCHANGEABLE MANUFACTURING. By 

J. V. Woodworth. 

A “shoppy” book, containing no theorizing, no problematical or experimental devices, there 
are no badly proportioned and impossible diagrams, no catalogue cuts, but a valuable collec¬ 
tion of drawings and descriptions of devices, the rich fruits of the author’s own experience. 
In its 500-odd pages the one subject only, Tool Making, and whatever relates thereto, is 
dealt with. The work stands without a rival. It is a complete practical treatise on the 
art of American Tool Making and system of interchangeable manufacturing as carried on 
to-day in the United States. In it are described and illustrated all of the different types 
and classes of small tools, fixtures, devices, and special appliances which are in general use 
in all machine manufacturing and metal working establishments where economy, capacity, 
and interchangeability in the production of machined metal parts are imperative. The 
science of jig making is exhaustively discussed, and particular attention is paid to drill jigs, 
boring, profiling and milling fixtures and other devices in which the parts to be machined 
are located and fastened within the contrivances. All of the tools, fixtures, and devices 
illustrated and described have been or are used for the actual production of work, such as 
parts of drill presses, lathes, patented machinery, typewriters, electrical apparatus, mechan¬ 
ical appliances, brass goods, composition parts, mould products, sheet metal articles, drop 
forgings, jewelry, watches, medals, coins, etc. 531 pages. Price. $4.00 

HENLEY’S ENCYCLOPEDIA OF PRACTICAL ENGINEERING AND ALLIED 
TRADES. Edited by Joseph G. Horner, A.M.I., M.E. 

This set of five volumes contains about 2,500 pages with thousands of illustrations, including 
diagrammatic and sectional drawings with full explanatory details. This work covers the 
entire practice of Civil and Mechanical Engineering. The best known expert in all branches 
of engineering have contributed to these volumes. The Cyclopedia is admirably well adapted 
to the needs of the beginner and the self-taught practical man, as well as the mechanical en¬ 
gineer, designer, draftsman, shop superintendent, foreman, and machinist. The work will be 
found a means of advancement to any progressive man. It is encyclopedic in scope, thorough 
and practical in its treatment of technical subjects, simple and clear in its descriptive matter, 
and without unnecessary technicalities or formulae. The articles are as brief as may be and 
yet give a reasonably clear and explicit statement of the subject, and are written by men who 
have had ample practical experience in the matters of which they write. It tells you all you 
want to know about engineering and tells it so simply, so clearly, so concisely, that one cannot 
help but understand. As a work of reference it is without a peer. $6.00 per volume. For 
complete set of five volumes, price. $25.00 

MACHINE SHOP ARITHMETIC. By Colvin-Cheney. 

This is an arithmetic of the things you have to do with daily. It tells you plainly about: how 
to find areas of figures; how to find surface or volume of balls or spheres; handy ways for 
calculating; about compound gearing; cutting screw threads on any lathe; drilling for taps; 
speeds of drills, taps, emery wheels, grindstones, milling cutters, etc.; all about the Metric 
system with conversion tables; properties of metals; strength of bolts and nuts; decimal 
equivalent of an inch. All sorts of machine shop figuring and 1,001 other things, any one of 
v/hich ought to be worth more than the price of this book to you, and it saves you the trouble 
of bothering the boss. 6th Edition. 131 pages. Price. 50 cents 

MODERN MACHINE SHOP CONSTRUCTION, EQUIPMENT AND MANAGEMENT. 

By Oscar E. Perrigo. 

The only work published that describes the Modern Machine Shop or Manufacturing Plant from 
the time the grass is growing on the site intended for it until the finished product is shipped. 
Just the book needed by those contemplating the erection of modern shop buildings, the re¬ 
building and reorganization of old ones, or the introduction of Modern Shop Methods, time and 
cost systems. It is a book written and illustrated by a practical shop man for practical shop 
men who are too busy to read theories and want facts. It is the most complete all-around 
book of its kind ever published. 400 large quarto pages. 225 original and specially-made 
illustrations. Price. $5.00 

MECHANICAL APPLIANCES, MECHANICAL MOVEMENTS AND NOVELTIES 
OF CONSTRUCTION. By Gardner D. Hiscox. 

This is a supplementary volume to the one upon mechanical movements. Unlike the first 
volume, which is more elementary in character, this volume contains illustrations and descrip¬ 
tions of many combinations of motions and of mechanical devices and appliances found in 
different lines of machinery. Each device being shown bv a line drawing with a description 


20 










CATALOGUE OF GOOD, PRACTICAL BOOKS 


niT k ,'“?J5 arts an , d ‘ he mothod of operation. From the multitude of devices de- 
k a i might be mentioned, in passing, such items as conveyors and elevators, 

Frony brakes, theimometers, 1 various types of boilers, solar engines, oil-fuel burners, condensers 
evaporators, Corliss and other valve gears, governors, gas engines, water motors of various 
descriptions, air ships, motors and dynamos, automobile and motor bicycles, railway block 
signals, car couplers, link and gear motions, ball bearings, breech block mechanism for heavy 
guns, and a large accumulation of others of equal importance. 1,000 specially made engrav¬ 
ings. 396 octavo pages. Price . . ... . $2.50 


MECHANICAL MOVEMENTS, POWERS, AND DEVICES. By Gardner D. Hiscox. 

This is a collection of 1,890 engravings of different mechanical motions and appliances, accom¬ 
panied by appropriate text, making it a book of great value to the inventor, the draftsman, 
and to all readers with mechanical tastes. The book is divided into eighteen sections or 
chapters in which the subject matter is classified under the following heads: Mechanical Powers- 
Transmission of Power; Measurement of Power, Steam Power; Air Power Appliances; Electric 
Power and Construction, Navigation and Roads; Gearing; Motion and Devices; Controlling 
Motion; Horological; Mining; Mill and Factory Appliances; Construction and Devices 
Drafting Devices: Miscellaneous Devices, etc. 12th edition, 400 octavo pages. Price $2.50 


MACHINE SHOP TOOLS AND SHOP PRACTICE. By W. H. Vandervoort. 

A work of 555 pages and 673 illustrations, describing in every detail the construction, operation, 
and manipulation of both hand and machine tools. Includes chapters on filing, fitting, and 
scraping surfaces; on drills, reamers, taps, and dies; the lathe and its tools; planers, shapers, 
and their tools; milling machines and cutters; gear cutters and gear cutting; drilling machines 
and drill work; grinding machines and their work; hardening and tempering; gearing, belting 
and transmission machinery: useful data and tables. 6th edition. Price .... $3.00 


THE MODERN MACHINIST. By John T. Usher. 

This is a book showing, by plain description and by profuse engravings, made expressly for 
the work, all that is best, most advanced, and of the highest efficiency in modern machine 
shop practice, tools, and implements, showing the way by which and through which, as Mr. 
Maxim says, “American machinists have become and are the finest mechanics in the world.’* 
Indicating as it does, in every line, the familiarity of the author with every detail of daily 
experience in the shop, it cannot fail to be of service to any man practically connected with 
the shaping or finishing of metals. 

There is nothing experimental or visionary about the book, all devices being in actual use 
and giving good results. It might be called a compendium of shop methods, showing a vari¬ 
ety of special tools and appliances which will give new ideas to many mechanics, from the 
superintendent down to the man at the bench. It will be found a valuable addition to any 
machinist’s library, and should be consulted whenever a new or difficult job is to be done, 
whether it is boring, milling, turning, or planing, as they are all treated in a practical manner. 
Fifth Edition. 320 pages. 250 illustrations. Price ... .$2.50 


MODERN MILLING MACHINES: THEIR DESIGN, CONSTRUCTION AND OPERA¬ 
TION. By Joseph G. Horner. 

This book describes and illustrates the Milling Machine and its work in such a plain, clear, 
and forceful manner, and illustrates the subject so clearly and completely, that the up-to-date 
machinist, student, or mechanical engineer cannot afford to do without the valuable infor¬ 
mation which it contains. It describes not only the early machines of this class, but notes 
their gradual development into the splendid machines of the present day, giving the design 
and construction of the various types, forms, and special features produced by prominent 
manufacturers, American and foreign. 

Milling cutters in all their development and modernized forms are illustrated and described, 
and the operations they are capable of producing upon different classes of work are carefully 
described in detail, and the speeds and feeds necessary are discussed, and valuable and useful 
data given for determining these usually perplexing problems. The book is the most compre¬ 
hensive work published on the subject. 304 pages. 300 illustrations. Price . . $4.00 

“ SHOP KINKS.” By Robert Grimshaw. 

A book of 400 pages and 222 illustrations, being entirely different froth any other book on 
machine shop practice. Departing from conventional style, the author avoids universal or 
common shop usage and limits his work to showing special ways of doing things better, more 
cheaply and more rapidly than usual. As a result the advanced methods of representative 
establishments of the world are placed at the disposal of the reader. This book shows the 
proprietor where large savings are possible, and how products may be improved, to the 
emnlovee it holds out suggestions that, properly applied, will hasten his advancement. No 
shop can afford to be without it. It bristles with valuable wrinkles and helpful suggestions. 
It will benefit all, from apprentice to proprietor. Every machinist, at any age. should study 
:ts pages, f ifth Edition. Price.. 


21 








CATALOGUE OF GOOD, PRACTICAL BOOKS 


THREADS AND THREAD CUTTING. By Colvin and Stabel. 

This clears up many of the mysteries of thread-cutting, such as double and triple threads, 
internal threads, catching threads, use of hobs, etc. Contains a lot of useful hints and several 
tables. 3rd Edition. Price. 25 cents 

TOOLS FOR MACHINISTS AND WOOD WORKERS, INCLUDING INSTRUMENTS 
OF MEASUREMENT. By Joseph G. Horner. 

The principles upon which cutting tools for wood, metal, and other substances are made are 
identical, whether used by the machinist, the carpenter, or by any other skilled mechanic in 
their daily work, and the object of this book is to give a correct and practical description of 
these tools as they are commonly designed, constructed, and used. 340 pages, fully illustrated. 
Price. $3.50 


MANUAL TRAINING 


ECONOMICS OF MANUAL TRAINING. By Louis Rouillion. 

The only book published that gives just the information needed by all interested in Manual 
Training, regarding Buildings, Equipment, and Supplies. Shows exactly what is needed for 
all grades of the work from the Kindergarten to the High and Normal School. Gives item¬ 
ized lists of everything used in Manual Training Work and tells just what it ought to cost. 
Also shows where to buy supplies, etc. Contains 174 pages, and is fully illustrated. 
2nd Edition. Price... $1.50 


MARINE ENGINEERING 


MARINE ENGINES AND BOILERS, THEIR DESIGN AND CONSTRUCTION. By 

Dr. G. Bauer, Leslie S. Robertson, and S. Bryan Donkin. 


In the words of Dr. Bauer, the present work owes its origin to an oft felt want of a Condensed 
Treatise, embodying the Theoretical and Practical Buies used in Designing Marine Engines 
and Boilers. The need for such a work has been felt by most engineers engaged in the con¬ 
struction and working of Marine Engines, not only by the younger men, but also by those of 
greater experience. The fact that the original German work was written by the chief engineer 
of the famous Vulcan Works, Stettin, is in itself a guarantee that this book is in all respects 
thoroughly up-to-date, and that it embodies all the information which is necessary for the 
design and construction of the highest types of marine engines and boilers. It may be said, 
that the motive power which Dr. Bauer has placed in the fast German liners that have been 
turned out of late years from the Stettin Works, represent the very best practice in marine 
engineering of the present day. 

This work is clearly written, thoroughly systematic, theoretically sound; while the character 
of its plans, drawings, tables, and statistics is without reproach. The illustrations are care¬ 
ful reproductions from actual working drawings, with some well-executed photographic views 
of completed engines and boilers. 744 pages. 550 illustrations and numerous tables. 

$9.00 net 


MODERN SUBMARINE CHART. 


A cross-section view, showing clearly and distinctly all the interior of a Submarine of the 
latest type. You get more information from this chart, about the construction and operation 
of a Submarine, than in any other way. No Details omitted—everything is accurate and to 
scale. It is absolutely correct in every detail, having been approved by Naval Engineers. 
All the machinery and devices fitted in a modern Submarine Boat are shown and to make the 
engraving more readily understood all the features are shown in operative form with Officers 
and Men in the act of performing the duties assigned to them in service conditions. This 
CHART IS REALLY AN ENCYCLOPEDIA OF A SUBMARINE. It is educational 
and worth many times its cost. Mailed in a Tube for.25 cents 


MINING 


ORE DEPOSITS, WITH A CHAPTER ON HINTS TO PROSPECTORS. By J. P. 

Johnson 

This book gives a condensed account of the ore-deposits at present known in South Africa 
It is also intended as a guide to the prospector. Only an elementary knowledge of geology 
and some mining experience are necessary in order to understand this work. With these 
qualifications, it will materially assist one in his search for metalliferous mineral occurrences 


22 
















CATALOGUE OF GOOD, PRACTICAL BOOKS 


bliities* of any COncerned - should enabte “> form some idea ot the possi- 

.. 

PHYSICS AND CHEMISTRY OF MINING. By T. H. Byrom. 

A practical work for the use of all preparing for examinations in mining or aualifvine- fnr 
colliery managers’ certificates. The aim of the author in this excellent boSk is to nlace dfarlv 
befoie the leader useful and authoritative data which .will render him valuable assistance in 
his studies The only work of its kind published. The information incorporlttd in ft wifi 
Pfoveof the greatest practical utility to students, mining engineers, colliery managers and 
others who are specially interested in the present-day treatment T minSI problems 
Amho C< TUff ntS an l chapters on: The Atmosphere; Laws Relating to the Behavior of 
Gases, rhe Diffusion of Gases; Composition of the Atmosphere: Sundry Constituents of the 
’ " a .^ r ’ Carbon; Fire-Damp; Combustion; Coal Dust and Its Action 1 Ex¬ 
plosives; Composition of Various Coals and Fuels; Methods of Analysis of CoaT Strata Ad¬ 
joining the Coal Measures; Magnetism and Electricity; Appendix. Useful Tables etc • 
Miscellaneous Questions. 160 pages. Illustrated. . ..... . . . . $2.00 

PRACTICAL COAL MINING. By T. H. Cockin. 

An important work, containing 428 pages and 213 illustrations, complete with practical de- 
tUoc W 1 ^ intuitively impart to the reader, not only a general knowdedge of the princi¬ 
ples of coal mining, but also considerable insight into allied subjects. This treatise is posi¬ 
tively up to date in every instance, and should be in the hands of every collierv engineer 
geologist, mine operator, superintendent, foreman, and all others who are interested in or 
connected with the industry. 2nd Edition.$2.50 

PATTERN MAKING 


PRACTICAL PATTERN MAKING. By F. W. Barrows. 

This is a very complete and entirely practical treatise on the subject of pattern making, illus¬ 
trating pattern work in wood and metal. From its pages you are taught just what you should 
know about pattern making. It contains a detailed description of the materials used by 
pattern makers, also the tools, both those for hand use, and the more interesting machine 
tools; having complete chapters on the band saw. The Buzz Saw, and the Lathe. Individual 
patterns of many different kinds are fully illustrated and described, and the mounting of 
metal patterns on plates for molding machines is included. 

Rules, Formulas and Tables are included, containing simple and original methods for finding 
the weight of castings, both from the pattern itself and from the drawings. This section 
contains some new and practical formulas, which will be found very useful in estimating 
weights, with the accuracy required for quotations to prospective customers. Ah of these 
rules are simple, and can be put to practical use by the ordinary, every-day man, and they 
have been proved by years of actual use. 

Plain rules for keeping down the cost of patterns, with a complete system for checking the 
cost of and marking the patterns, and a card record showing what the pattern is, material 
used, where located in safe, with its cost and date of production, is included. The book closes 
with an original and practical method for the inventory and valuation of patterns. Con¬ 
taining 326 pages and 150 detailed illustrations. Price. $2.00 


PERFUMERY 


HENLEY’S TWENTIETH CENTURY BOOK OF RECEIPTS, FORMULAS AND PRO¬ 
CESSES. Edited by G. D. Hiscox. 

The most valuable Techno-chemical Receipt Book published. Contains over 10,000 practical 
receipts, many of which will prove of special value to the perfumer, a mine of information, up- 
to-date in every respect. Price, Cloth, $3.00; half morocco.$4.00 

PERFUMES AND THEIR PREPARATION. By G. W. Askinson, Perfumer. 

A comprehensive treatise, in which there has been nothing omitted that could be of value 
to the Perfumer. Complete directions for making handkerchief perfumes, smelling-salts, 
sachets, fumigating pastilles: preparations for the care of the skin, the mouth, the hair, cos¬ 
metics, hair dyes and other toilet articles are given, also a detailed description of aromatic 
suDstances: their nature, tests of purity, and wholesale manufacture._ A book of general, 
as well as professional interest, meeting the wants not only of the druggist and perfume man¬ 
ufacturer, but also of the general public. Third edition. 312 pages. Illustrated. . $3.00 

23 


l 















CATALOGUE OF GOOD, PRACTICAL BOOKS 


PLUMBING 


MECHANICAL DRAWING FOR PLUMBERS. By R. M. Starbuck. 

A concise, comprehensive and practical treatise on the subject of mechanical drawing in its 
various modern applications to the work of all who are in any way connected with the 
plumbing trade. Nothing will so help the plumber in estimating and in explaining work to 
customers and workmen as a knowledge of drawing, and to the workman it is of inestimable 
value if he is to rise above his position to positions of greater responsibility. Among the 
chapters contained are: 1. Value to plumber of knowledge of drawing; tools required 
and their use; common views needed in mechanical drawing. 2. Perspective versus mechan¬ 
ical drawing in showing plumbing construction. 3. Correct and incorrect methods in 
plumbing drawing; plan and elevation explained. 3. Floor and cellar plans and elevation; 
scale drawings; use of triangles. 5. Use of triangles; drawing of fittings, traps, etc. 6. 
Drawing plumbing elevations and fittings. 7. Instructions in drawing plumbing elevations. 
8. The drawing of plumbing fixtures; scale drawings. 9. Drawing of fixtures and fittings. 
10. Inking of drawings. 11. Shading of drawings. 12. Shading of drawings. 13. Sec¬ 
tional drawings; drawing of threads. 14. Plumbing elevations from architect’s plan. 
15. Elevations of separate parts of the plumbing system. 16. Elevations from architect’s 
plans. 17. Drawing of detail plumbing connections. 18. Architect’s plans and plumbing 
elevations of residence. 19. Plumbing elevations of residence (continued); plumbing plans 
for cottage. 20. Plumbing elevations; roof connections. 21. Plans and plumbing eleva¬ 
tions for six-flat building. 22. Drawing of various parts of the plumbing system; use of 
scales. 23. Use of architect’s scales. 24. Special features in the illustrations of country 
plumbing. 25. Drawing of wrought iron piping, valves, radiators, coils, etc. 26. Drawing 
of piping to illustrate heating systems. 150 illustrations. Price.$1.60 

MODERN PLUMBING ILLUSTRATED. By R. M. Starbuck. 

This book represents the highest standard of plumbing work. It has been adopted and used 
as a reference book by the United States Government, in its sanitary work in Cuba, Porto 
Rico, and the Philippines, and by the principal Boards of Health of the United States and 
Canada. 

It gives connections, sizes and working data for all fixtures and groups of fixtures. Tt is 
helpful to the master plumber in demonstrating to his customers and in figuring work. It 
gives the mechanic and student quick and easy access to the best modern plumbing practice. 
Suggestions for estimating plumbing construction are contained in its pages. This book 
represents, in a word, the latest and best up-to-date practice, and should be in the hands of 
every architect, sanitary engineer and plumber who wishes to keep himself up to the minute 
on this important feature of construction. Contains following chapters, each illustrated 
with a full-page plate: Kitchen sink, laundry tubs, vegetable wash sink; lavatories, 
pantry sinks, contents of marble slabs; bath tub, foot and sitz bath, shower bath; water 
closets, venting of water closets; low-down water closets, water closets operated by flush 
valves, water closet range; slop sink, urinals, the bidet; hotel and restaurant sink, grease 
trap; refrigerators, safe wastes, laundry waste; lines of refrigerators, bar sinks, soda foun¬ 
tain sinks; horse stall, frost-proof water closets; connections for S traps, venting; con¬ 
nections for drum traps; soil pipe connections; supporting of soil pipe; main trap and 
fresh air inlet; floor drains and cellar drains, subsoil drainage; Avater closets and floor 
connections; local venting; connections for bath rooms; connections for bath rooms, con¬ 
tinued; connections for bath rooms, continued; connections for bath rooms, continued; 
examples of poor practice; roughing-work ready for test; testing of plumbing system; 
method of continuous venting; continuous venting for tAVO-floor work; continuous A’enting 
for two lines of fixtures on three or more floors; continuous venting of Avater closets; plumb¬ 
ing for cottage house; construction for cellar piping; plumbing for residence, use of special 
fittings; plumbing for two-flat house; plumbing for apartment building; plumbing for 
double apartment building; plumbing for office building; plumbing for public toilet rooms; 
plumbing for public toilet rooms, continued; plumbing for bath establishment; plumbing 
for engine house, factory plumbing; automatic flushing for schools, factories, etc.; use of 
flushing \ r alves; urinals for public toilet rooms; the Durham system, the destruction of 
pipes by electrolysis; construction of work Avithout use of lead; Automatic sewage lift, 
automatic sump tank; country plumbing; construction of cesspools; septic tank and auto¬ 
matic sewage siphon; country plumbing; water supply for country house; thawing of 
Avater mains and service by electricity; double boilers; hot water supply of large build¬ 
ings ; automatic control of hot water tank; suggestions for estimating plumbing construc¬ 
tion. 400 octavo pages, fully illustrated by 55 full-page engravings. Price . $4.00 

STANDARD PRACTICAL PLUMBING. By R. M. Starbuck. 

A complete practical treatise of 450 pages covering the subject of Modern Plumbing 
in all its branches, a large amount of space being devoted to a very complete and practical 
treatment of the subject of Hot Water Supply and Circulation and Range Boiler Work. 
Its thirty chapters include about every phase of the subject one can think of, making it 




24 










CATALOGUE OF GOOD, PRACTICAL BOOKS 


\ 


an indispensable work to the master plumber, the journeyman plumber, and the apprentice 
plumber, containing chapters on: the plumber’s tools; wiping solder, composition and use- 
joint wiping; lead work; traps; siphonage of traps; venting; continuous venting- house 
sewer and sewer connections; house drain; soil piping, roughing; main trap and fresh air 
inlet; floor, yard, cellar drains, rain leaders, etc.; fixture wastes: water closets; ventilation- 
improved plumbing connections; residence plumbing; plumbing for hotels, schools fac¬ 
tories, stables, etc.; modern country plumbing; filtration of sewage and water supply- 
hot and cold supply; range boilers; circulation; circulating pipes; range boiler problems’ 
hot water for large buildings; water lift and its use; multiple connections for hot water 
boilers; heating c>f radiation by supply system; theory for the plumber; drawing for the 
plumber. Fully illustrated by 347 engravings. Price.$3.00 


RECEIPT BOOK 


HENLEY’S TWENTIETH CENTURY BOOK OF RECEIPTS, FORMULAS AND PRO¬ 
CESSES. Edited by Gardner D. Hiscox. 

The most valuable Techno-chemical Receipt Book published, including over 10,000 selected 
scientific, chemical, technological, and practical receipts and processes. 

This is the most complete Book of Receipts ever published, giving thousands of receipts for 
the manufacturer of valuable articles for everyday use. Hints, Helps, Practical Ideas, and 
Secret Processes are revealed within its pages. It covers every branch of the useful arts and 
tells thousands of ways of making money and is just the book everyone should have at his 
command. 

Modern in its treatment of every subject that properly falls within its scope, the book may 
truthfully be said to present the very latest formulas to be foimd in the arts and industries 
and to retain those processes which long experience has proven worthy of a permanent record 
To present here even a limited number of the subjects which find a place in this valuable 
work would be difficult. Suffice to say that in its pages will be found matter of intense in¬ 
terest and immeasurable practical value to the scientific amateur and to him who wishes to 
obtain a knowledge of the many processes used in the arts, trades and manufactures, a 
knowledge which will render his pursuits more instructive and remunerative. Serving as a 
reference book to the small and large manufacturer and suppplying intelligent seekers with 
the information necessary to conduct a process, the work will be found of inestimable worth 
to the Metallurgist, the Photographer, the Perfumer, the Painter, the Manufacturer of 
Glues, Pastes, Cements, and Mucilages, the Compounder of Alloys, the Cook, the Physician, 
the Druggist, the Electrician, the Brewer, the Engineer, the Foundryman, the Machinist, 
the Potter, the Tanner, the Confectioner, the Chiropodist, the Manicure, the Manufacturer 
of Chemical Novelties and Toilet Preparations, the Dyer, the Electroplater, the Enameler, 
the Engraver, the Provisioner, the Glass 'Yorker, the Goldbeater, the Watchmaker, the Jew¬ 
eler, the Hat Maker, the Ink Manufacturer, the Optician, the Farmer, the Dairyman, the 
Paper Maker, the Wood and Metal Worker, the Chandler and Soap Maker, the Veterinary 
Surgeon, and the Technologist in general. 

A mine of information, and up-to-date in every respect. A book which will prove of value 
to EVERYONE, as it covers every branch of the Useful Arts. 800 pages. Price $3.00 

WHAT IS SAID OF THIS BOOK: 


“Your Twentieth Century Book of Receipts, Formulas and Processes duly received. I am 
glad to have a copy of it, and if I could not replace it money couldn’t buy it. It is the best 
thing of the sort I ever saw.” (Signed) M. E. Trux, 

Sparta, Wis. 

“ There are few persons who would not be able to find in the book some single formula that 
would repay several times the cost of the book.”— Alerchant's Record and Show Window. 


RUBBER 


RUBBER HAND STAMPS AND THE MANIPULATION OF INDIA RUBBER. By 

T. O’Conor Sloane. 

This book gives full details on all points, treating in a concise and simple manner the elements 
of nearly everything it is necessary to understand for a commencement in any branch of the 
India Rubber Manufacture. The making of all kinds of Rubber Hand Stamps, Small Articles 
of India Rubber, U. S. Government Composition, Dating Hand Stamps, the Manipulation 
of Sheet Rubber, Toy Balloons. India Rubber Solutions, Cements, Blackings, Renovating 


25 











CATALOGUE OF GOOD, PRACTICAL BOOKS 


Varnish, and Treatment for India Rubber Shoes, etc.; the Hektograph Stamp Inks, and 
Miscellaneous Notes, with a Short Account of the Discovery, Collection, and Manufacture of 
India Rubber are set forth in a manner designed to be readily understood, the .explanations 
being plain and simple. Including a chapter on Rubber Tire Making and Vulcanizing; also a 
chapter on the uses of rubber in Surgery and Dentistry. Third revised and enlarged edition. 
175 pages. Illustrated. . .. $1.00 


SAWS 


SAW FILINGS AND MANAGEMENT OF SAWS. By Robert Grimshaw. 


A practical hand book on filing, gumming, swaging, hammering, and the brazing of band saws, 
the speed, work, and power to run circular saws, etc. A handy book for those who have charge 
of saws, or for those mechanics who do their own filing, as it deals with the proper shape and 
pitches of saw teeth of all kinds and gives many useful hints and rules for gumming, setting, 
and filing, and is a practical aid to those who use saws for any purpose. New edition, revised 
and enlarged. Illustrated. Price. $1.00 


STEAM ENGINEERING 


AMERICAN STATIONARY ENGINEERING. By W. E. Crane. 

This book begins at the boiler room and takes in the whole power plant. A plain talk on 
every-day work about engines, boilers, and their accessories. It is not intended to be scien¬ 
tific or mathematical. All formulas are in simple form so that any one understanding plain 
arithmetic can readily understand any of them. The author has made this the most prac¬ 
tical book in print; has given the results of his years of experience, and has included about 
ill that has to do with an engine room or a power plant. You are not left to guess at a single 
joint. You are shown clearly what to expect under the various conditions; how to secure 
the best results; ways of preventing “shut downs” and repairs; in short, all that goes to 
make up the requirements of a good engineer, capable of taking charge of'a plant. It’s plain 
enough for practical men and yet of value to those high in the profession. 

\ partial list of contents is: The boiler room, cleaning boilers, firing, feeding; pumps; 
nspection and repair; chimneys, sizes and cost; piping; mason work; foundations; testing 
jement; pile driving; engines, slow and high speed; valves; valve setting; Corliss engines, 
setting valves, single and double eccentric; air pumps and condensers; different types of 
condensers; water needed; lining up; pounds; pins not square in crosshead or crank; 
engineers’tools; pistons and piston rings; bearing metal; hardened copper; drip pipes from 
cylinder jackets; belts, how made, care of; oils; greases; testing lubricants; rules and 
tables, including steam tables; areas of segments; squares and square root; cubes and cube 
root; areas and circumferences of circles. Notes on: Brick work; explosions; pumps; 
pump valves; heaters, economizers; safety valves; lap, lead, and clearance. Has a complete 
examination for a license, etc., etc. Second edition. 285 pages. Illustrated. Price . $2.00 

EMINENT ENGINEERS. By Dwight Goddard. 

Everyone who appreciates the effect of such great inventions as the Steam Engine, Steamboat, 
Locomotive, Sewing Machine, Steel Working, and other fundamental discoveries, is interested 
in knowing a little about the men who made them and their achievements. 

Mr. Cloddard has selected thirty-two of the world’s engineers who have contributed most 
largely to the advancement of our civilization by mechanical means, giving only such facts as 
are of general interest and in a way which appeals to all, whether mechanics or not. 280 
pages. 35 illustrations. Price. $1.50 

ENGINE RUNNER’S CATECHISM. By Robert Grimshaw. 

A practical treatise for the stationary engineer, telling how to erect, adjust and run the prin¬ 
cipal steam engines in use in the United States. Describing the principal features of various 
special and well-known makes of engines: Temper Cut-off, Shipping and Receiving Founda¬ 
tions, Erecting and Starting, Valve Setting, Care and Use, Emergencies, Erecting and Ad¬ 
justing Special Engines. 

The questions asked throughout the catechism are plain and to the point, and the answers 
are given in such simple language as to be readily understood by anyone. All the instructions 
given are complete and up-to-date; and they are written in a popular style, without any 
technicalities or mathematical formula. The work is of a handy size for the pocket, clearly 
and well printed, nicely bound, and profusely illustrated. To young engineers this catechism 

26 











CATALOGUE OF GOOD, PRACTICAL BOOKS 


will be of great value., especially to those who mav be nremrino- tr> ™ , * , 

for certifi ates of competency; and to engineers generallv^fTin to b ? exami £ ed 

will find in this volume more really pracS^ « th ^ 

where else within a like compass. 387 pages. ' Seventh edition 1 p?i^e be f ? UI $ 2 a $o 

ENGINE TESTS AND BOILER EFFICIENCIES. By J. Buchetti. 

This work fully describes and illustrates the method of testing the power of steam engine* 
turbines and explosive motors. The properties of steam and the evaporative power offK 

25Tp\ U S n i7f U , l U u?tS?onf 1Inn ? y draft; With f ° rmUla3 ex P ,ained « PracUca P l?y We co™' 

.° • $3.00 

HORSEPOWER CHART. 

Shows the horsepower of any stationary engine without calculation No matter what ttm 
cylinder diameter of stroke;, the steam pressure or cut off; the revolutions whether con 
densmg or non-condensing, it’s all there. Easy to use, accurate, and saves time and caS 
lations. Especially useful to engineers and designers. . 5 q cents 

MODERN STEAM ENGINEERING IN THEORY AND PRACTICE. By Gardner 
D. Hiscox. 

This is a complete and practical work issued for Stationary Engineers and firemen dealing 
with the care and management of boilers, engines, pumps, superheated steam refrigerating 
machinery, dynamos, motors, elevators, air compressors, and all other branches with which 
the modern engineer must be familiar. Nearly 200 questions with their answers on steam 
and electrical engineering, likely to be asked by the Examining Board, are included. 

Among the chapters are: Historical; steam and its properties; appliances for the genera¬ 
tion of steam; types of boilers; chimney and its work; heat economy of the feed water 
steam pumps and their work; incrustation and its work; steam above atmospheric pressure 
flow of steam from nozzles; superheated steam and its work; adiabatic expansion of steam 
indicator and its work; steam engine proportions; slide valve engines and valve motion 
Corliss engine and its valve gear; compound engine and its theory; triple and multiple 
expansion engine, steam turbine; refrigeration; elevators and their management- cost 
of power; steam engine troubles; electric power and electric plants. 487 pages 405 en¬ 
gravings. Price.$3.00 


STEAM ENGINE CATECHISM. By Robert Grimshaw. 

This unique volume of 413 pages is not only a catechism on the question and answer princi¬ 
ple; but it contains formulas and worked-out answers for all the Steam problems that apper¬ 
tain to the operation and management of the Steam Engine. Illustrations of various valves 
and valve gear with their principles of operation are given. Thirty-four Tables that are 
indispensable to every engineer and fireman that wishes to be progressive and is ambitious to 
become master of his calling are within its pages. It is a most valuable instructor in the 
service of Steam Engineering. Leading engineers have recommended it as a valuable educa¬ 
tor for the beginner as well as a reference book for the engineer. It is thoroughly indexed 
for every detail. Every essential question on the Steam Engine with its answer is contained 
in this valuable work. Sixteenth edition. Price.$2.00 


STEAM ENGINEER’S ARITHMETIC. By Colvin-Cheney. 

A practical pocket book for the steam engineer. Shows how to work the problems of the 
engine room and shows “why.” Tells how to figure horse-power of engines and boilers; area 
of boilers; has tables of areas and circumferences; steam tables; has a dictionary of engineering 
terms. Puts you on to all all of the little kinks in figuring whatever there is to figure around 
a power plant. Tells you about the heat unit; absolute zero; adiabatic expansion; duty of 
engines; factor of safety; and 1,001 other things; and everything is plain and simple—not 
the hardest way to figure, but the easiest. 2nd Edition.50 cents 


STEAM HEATING AND VENTILATION 


PRACTICAL STEAM, HOT-WATER HEATING AND VENTILATION. By A. G. 

King. 

This book is the standard and latest work published on the subject and has been prepared for 
the use of all engaged in the business of steam, hot water heating, and ventilation. It is an 
original and exhaustive work. Tells how to get heating contracts, how to install heating and 
ventilating apparatus, the best business methods to be used, with “Tricks of the Trade” for 


2 7 










CATALOGUE OF GOOD, PRACTICAL BOOKS 


shoo use. Rules and data for estimating radiation and cost and such tables and information 
as make it an indispensable work for everyone interested in steam, hot water heating, and venti¬ 
lation. It describes all the principal systems of steam, hot water, vacuum, vapor, and vacuum- 
vapor heating, together with the new accelerated systems of hot water circulation, including 
chapters on up-to-date methods of ventilation and the fan or blower system of heating and 
ventilation. Containing chapters on: I. Introduction. II. Heat. III. Evolution of 
artificial heating apparatus. IV. Boiler surface and settings. V. The chimney flue. VI. 
Pipe and fittings. VII. Valves, various kinds. VIII. Forms of radiating surfaces. IX. 
Locating of radiating surfaces. X. Estimating radiation. XI. Steam-heating apparatus. 
XII. Exhaust-steam heating. XIII. Hot-water heating. XIV. Pressure systems of hot- 
water work. XV. Hot-water appliances. XVI. Greenhouse heating. XVII. Vacuum 
vapor and vacuum exhaust heating. XVIII. Miscellaneous heating. XIX. Radiator and 
pipe connections. XX. Ventilation. XXI. Mechanical ventilation and hot-blast heating. 
XXII. Steam appliances. XXIII. District heating. XXIV. Pipe and boiler covering. 
XXV. Temperature regulation and heat control. XXVI. Business methods. XXVII. 
Miscellaneous. XXVIII. Rules, tables and useful information. 367 pages. 300 detailed 
engravings. Price .. $3.00 


STEAM PIPES 


STEAM PIPES: THEIR DESIGN AND CONSTRUCTION. By Wm. H. Booth. 

The work is well illustrated in regard to pipe joints, expansion offsets, flexible joints, and 
self-contained sliding joints for taking up the expansion of long pipes. In fact, the chapters 
on the flow of steam and expansion of pipes are most valuable to all steam fitters and users. 
The pressure strength of pipes and method of hanging them are well treated and illustrated. 
Valves and by-passes are fully illustrated and described, as are also flange joints and their 
proper proportions, exhaust heads and separators. One of the most valuable chaDters is that 
on superheated steam and the saving of steam by insulation with the various kinds of felt¬ 
ing and other materials with comparison tables of the loss of heat in thermal units from naked 
and felted steam pipes. Contains 187 pages. Price. $2.00 


STEEL 


AMERICAN STEEL WORKER. By E. R. Markham. 

This book tells how to select, and how to work, temper, harden, and anneal steel for everything 
on earth. It doesn’t tell how to temper one class of tools and then leave the treatment of 
another kind of tool to your imagination and judgment, but it gives careful instructions for 
every detail of every tool, whether it be a tap, a reamer or just a screw-driver. It tells about 
the tempering of small watch springs, the hardening of cutlery, and the annealing of dies In 
fact there isn’t a thing that a steel worker would want to know that isn’t included. It is the 
standard book on selecting, hardening, and tempering all grades of steel. Among the 
chapter headings might be mentioned the following subjects: Introduction: the workman- 
steel; methods of heating; heating tool steel; forging; annealing; hardening baths; baths 
for hardening; hardening steel; drawing the temper after hardening; examples of hard¬ 
ening; pack hardening; case hardening; spring tempering; making tools of machine steel- 
special steels; steel for various tools; causes of trouble; high speed steels, etc. 366 pages 
Very fully illustrated. 3rd Edition. Price. $2.50 

HARDENING, TEMPERING, ANNEALING, AND FORGING OF STEEL. By J. V. 

Woodworth. 

A new work treating in a clear, concise manner all modern processes for the heating annealing 
forging, welding, hardening, and tempering of steel, making it a book of great practical value 
to the metal-working mechanic in general, with special directions for the successful hardening 
and tempering of all steel tools used in the arts, including milling cutters, taps thread dies 
reamers, both solid and shell, hollow mills, punches and dies, and all kinds of sheet metal 
working tools, shear blades, saws, fine cutlery, and metal cutting tools of all description as 
well as for all implements of steel both large and small. In this work the simplest and rriost 
satisfactory hardening and tempering processes are given. 

The uses to which the leading brands of steel may be adapted are concisely presented and their 
treatment for working under different conditions explained, also the special methods for the 
hardening and tempering of special brands. 

A chapter devoted to the different processes for Case-hardening is also included and special 
reference made to the adoption of machinery steel for tools of various kinds. 4th Edition. 288 
pages. 201 Illustrations. Price. a»o 


28 












CATALOGUE OF GOOD, PRACTICAL BOOKS 


TURBINES 


MARINE STEAM TURBINES. By Dr. G. Bauer and 0. Lasche. Assisted by 
E. Ludwig and H. Vogel. Translated from the German and edited by M. G. S. 
Swallow. 

This work forms a supplementary volume to the book entitled “Marine Engines and Boilers.” 
The authors of this book, Dr. G. Bauer and O. Lasche, may be regarded as the leading 
authorities on turbine construction. 

The book is essentially practical and discusses turbines in which the full expansion of steam 
passes through a number of separate turbines arranged for driving two or more shafts, as 
in the Parsons system, and turbines in which the complete expansion of steam from inlet 
to exhaust pressure occurs in a turbine on one shaft, as in the case of the Curtis machines. 
It will enable a designer to carry out all the ordinary calculations necessary for the con¬ 
struction of steam turbines, hence it fills a want which is hardly met by larger and more 
theoretical works. 

Numerous tables, curves and diagrams will be found, which explain with remarkable lucidity 
the reason why turbine blades are designed as they are, the course which steam takes through 
turbines of various types, the thermodynamics of steam turbine calculation, the influence 
of vacuum on steam consumption of steam turbines, etc. In a word, the very information 
which a designer and builder of steam turbines most requires. The book is divided into 
parts as follows: 1. Introduction. 2. General remarks on the design of a turbine installa¬ 
tion. 3. The calculation of steam turbines. 4. Turbine design. 5. Shafting and pro¬ 
pellers. 6. Condensing plant. 7. Arrangement of turbines. 8. General remarks on the 
arrangement of steam turbines in steamers. 9. Turbine-driven auxiliaries. 10. Tables. 
Large octavo. 214 pages. Fully illustrated and containing 18 tables. Including an entropy 
chart. Price, net.$3.50 


WATCH MAKING 


WATCHMAKER’S HANDBOOK. By Claudius Saunier. 

This famous work has now reached its seventh edition and there is no work issued that can 
compare to it for clearness and completeness. It contains 498 pages and is intended as a 
workshop companion for those engaged in Watch-making and allied Mechanical Arts. Nearly 
250 engravings and fourteen plates are included. Price ... .... $3.00 


29 






































































































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